 Casio F-91W-1 watch with a resin case and resin strap | |
| Manufacturer | Casio |
|---|---|
| Type | Quartz |
| Display | Digital |
| Introduced | June 1989 [1] |
The Casio F-91W is a digital watch manufactured by Japanese electronics company Casio. Introduced in June 1989 [1] as a successor of the F-87W, [2] it is popular for its low price, long battery life and iconic design. [3] As of 2011, annual production of the watch is 3 million units, which makes it the most sold watch in the world. [4]
Designed by Ryūsuke Moriai as his first design for Casio, [5] the case of the F-91W measures 37.5 by 34.5 by 8.5 millimetres (1.48 by 1.36 by 0.33 in). The case is primarily made of resin, [6] with a stainless steel caseback and buttons, with the manufacturer's module number, 593, stamped on the caseback. The resin strap is 18 millimetres (0.71 in) at the fitting and 22 mm across the widest part of the lugs. The total weight is 21 grams (0.74 oz).
The F-91W has a chronograph, featuring precision of 1⁄100 seconds with a count up to 59:59.99 (nearly one hour). The chronograph is also able to mark net and split times (i.e. laps). Other features include an hourly time beep, a single daily alarm lasting 20 seconds and an annual calendar. The watch does not make allowances for leap years as there is no provision to record the year. Due to this, the month of February is always counted as 28 days. [7] The watch uses a faint, green LED backlight located at the left of the display for illumination (in earlier units it was an amber microlight). According to the manufacturer estimates, the watch is reported to be accurate to ±30 seconds per month. [7]
The quartz movement, designated Module 593, is powered by a single CR2016 3-volt lithium button cell rated to a stated battery life of 7 years. [8]
The front of the watch is marked "Water Resist". [7] The black version (F91W-1) [9] is "30 meter / 3 bar" (i.e. 100 feet / 44 psi), the ISO standard meaning of which is: "Suitable for everyday use. Splash/rain resistant. NOT suitable for showering, bathing, swimming, snorkeling, water related work and fishing".
The watch is controlled by three side-mounted push-buttons.
The time or date is adjusted by pressing the lower left button three times to bring the watch to time adjustment mode. The top left button is used to cycle through seconds, hours, minutes, month, date, day and normal mode. The right button is used to adjust the flashing value displayed. Unlike any other value, the seconds can only be zeroed. Should this happen before 30 seconds, the watch will zero in at the beginning of the current minute. After 30 seconds it will start the next minute as displayed. When the adjustments are finished, the bottom left button can be pressed once to return the watch to normal mode.
The watch display shows the day of the week, day of the month, hour, minute, seconds and the signs PM in the afternoon – or 24H (24-hour clock) – at all times, the alarm signal status (bar of vertical lines), and the hourly signal status (double beep on the hour, shown as a bell) are present when activated in the alarm mode.
In stopwatch mode, minutes, seconds and hundredths of a second are shown.
The US government became suspicious of Afghans who wore Casio watches due to their ability to be used as timers for improvised explosive devices, a tactic favored by al-Qaeda. [11] [12]
According to secret documents issued to interrogators at Guantanamo Bay, obtained [13] and released by The Guardian , "the Casio F-91W digital watch was declared to be 'the sign of al-Qaeda' and a contributing factor to continued detention of prisoners by the analysts stationed at Guantanamo Bay. Briefing documents used to train staff in assessing the threat level of new detainees advise that possession of the F-91W and the A159W, available online for as little as £4, suggests the wearer has been trained in bomb making by al-Qaeda in Afghanistan." [14] United States military intelligence officials have identified the F-91W as a watch that terrorists use in constructing time bombs. [15] [16] [17] [18]
This association was highlighted in the Denbeaux study, and may have been used in some cases at Guantanamo Bay. [19] An article published in The Washington Post in 1996 reported that Abdul Hakim Murad, Wali Khan Amin Shah, and Ramzi Ahmed Yousef had developed techniques to use commonly available Casio digital watches to detonate time bombs. [20] Casio watches were mentioned almost 150 times in prisoner assessments from Guantanamo. [21]
On 12 July 2006, the magazine Mother Jones provided excerpts from the transcripts of a selection of the Guantanamo detainees. [17] The article informed readers:
More than a dozen detainees were cited for owning cheap digital watches, particularly "the infamous Casio watch of the type used by Al Qaeda members for bomb detonators."
The article quoted Abdullah Kamel Abdullah Kamel Al Kandari:
When they told me that Casios were used by Al Qaeda and the watch was for explosives, I was shocked... If I had known that, I would have thrown it away. I'm not stupid. We have four chaplains [at Guantanamo]; all of them wear this watch.
| Model name | Description |
|---|---|
| F-91W-3, F-91WG-9 | Similar to the original F-91W, but including a green and gold trim respectively on the face. [22] |
| F-91-WB series | Simplified case print, print on face and strap: blue-gray on black, bronze on black, white on blue, gray on white. [23] |
| F-91-WC series | Neon colors for case, face and strap: orange, blue, green, pink, beige and yellow. [24] |
| F-91-WM series | Metallic colored cases with black straps: grey, army green, blue, silver and gold. |
| F-91-WS series | Translucent straps with muted case colors: blue, pink, white, and grey [25] |
| F-84W | Japanese Domestic Market (JDM) model. Uses the same 593 module, but the case design is more similar to the older F-28W and F-87W. It has lugs instead of an embedded strap. |
| F-94W | Circular icon arrangement in the display. |
| W59 | Black case with rounded corners and blue accents on the face. Waterproof up to 50 meters. |
| A158W, A159W, A163W, A164W | Chrome plated case, stainless steel band. |
| A159WGEA-1 | Ion plated gold stainless steel band, gold colored chrome plated case. |
| F-105W, A168W, A168WG, A168WEGM, A168WEM, W-86 | Equipped with electroluminescent backlighting instead of the LED backlight in the other variants. Available in black color with a resin strap or in silver or gold colors with a stainless steel bracelet. Slightly different icon arrangement on the display and a thicker case due to the backlight system. Some versions also feature a negative display. |
| LA680 | A smaller variant, marketed towards women |
Counterfeits of this watch are very common, despite its low price tag. These counterfeits generally have a lower plastic build quality, narrower LCD viewing angles, louder and higher-pitched beeps, and significantly less accurate timekeeping than genuine models. [26] The newer modules with the green LED light can be tested by holding the right button for over 3 seconds in the main timekeeping mode; this will lead the display to show "CASIo", as a test for authenticity. With the advancement in technology, however, some counterfeit models have also been developed to show this sign, although these are fairly uncommon. This leaves the only method of distinguishing them as assessing the overall build quality, timekeeping accuracy, display viewing angle and the printing on the screen glass. [26] [27]
A watch is a portable timepiece intended to be carried or worn by a person. It is designed to keep a consistent movement despite the motions caused by the person's activities. A wristwatch is designed to be worn around the wrist, attached by a watch strap or other type of bracelet, including metal bands, leather straps, or any other kind of bracelet. A pocket watch is designed for a person to carry in a pocket, often attached to a chain. A stopwatch is a watch that measures intervals of time.
Casio Computer Co., Ltd. is a Japanese multinational electronics manufacturing corporation headquartered in Shibuya, Tokyo, Japan. Its products include calculators, mobile phones, digital cameras, electronic musical instruments, and analogue and digital watches. It was founded in 1946, and in 1957 introduced the first entirely compact electronic calculator. It was an early digital camera innovator, and during the 1980s and 1990s, the company developed numerous affordable home electronic keyboards for musicians along with introducing the first mass-produced digital watches.
A pocket watch is a watch that is made to be carried in a pocket, as opposed to a wristwatch, which is strapped to the wrist.
Seiko Group Corporation, commonly known as Seiko, is a Japanese maker of watches, clocks, electronic devices, semiconductors, jewelry, and optical products. Founded in 1881 by Kintarō Hattori in Tokyo, Seiko introduced the world's first commercial quartz wristwatch in 1969.
Bulova is an American timepiece manufacturing company that was founded in 1875 and has been owned by Japanese multinational conglomerate Citizen Watch Co. since 2008. The company makes watches, clocks and accessories, and it is based in New York City.
A stopwatch is a timepiece designed to measure the amount of time that elapses between its activation and deactivation.
A chronograph is a specific type of watch that is used as a stopwatch combined with a display watch. A basic chronograph has hour and minute hands on the main dial to tell the time, a small seconds hand to tell that the watch is running, and a seconds hand on the main dial usually equipped with a sweeping movement for precision accompanied by a minutes sub dial for the stopwatch. Another sub dial to measure the hours of the stopwatch may also be included on a chronograph. The stopwatch can be started, stopped, and reset to zero at any time by the user by operating pushers usually placed adjacent to the crown. More complex chronographs often use additional complications and can have multiple sub-dials to measure more aspects of the stopwatch such as fractions of a second as well as other helpful things such as the moon phase and the local 24-hour time. In addition, many modern chronographs include tachymeters on the bezels for rapid calculations of speed or distance. Louis Moinet invented the chronograph in 1816 for use in tracking astronomical objects. Chronographs soon found a widespread use in artillery fire in the mid to late 1800s. Over time, the chronograph found its use to be in several different fields, such as aircraft piloting, auto racing, diving and submarine maneuvering.
The G-Shock is a line of watches manufactured by the Japanese electronics company Casio, designed to resist mechanical stress, shock and vibration. G-Shock is an abbreviation for Gravitational Shock. The watches in the G-Shock line are designed primarily for sports, military and outdoors-oriented activities; all G-Shocks have a chronograph feature, 200 metre water resistance and an alarm, with either a digital display, analogue display or a combination of analogue and digital displays. Other features such as a countdown timer, world clock, and a backlight are included in most models. Newer high-end models in the line also feature GPS, directional, pressure and temperature sensors, radio-controlled time adjustment and Bluetooth time adjustment achieved by connecting the watch to a smartphone via a dedicated application.
Zenith SA is a Swiss luxury watchmaker. The company was started in 1865 by Georges Favre-Jacot in Le Locle in the canton of Neuchâtel and is one of the oldest continuously operating watchmakers. Favre-Jacot invented the concept of "in house movements", believing that only through control of the entire watchmaking process could the highest quality be achieved. Zenith was purchased by LVMH in November 1999, becoming one of several brands in its watch and jewelry division, which includes TAG Heuer and Hublot. Benoit de Clerck is the company's current president and CEO.
In horology, a complication is any feature of a timepiece beyond the display of hours, minutes and seconds. A timepiece indicating only hours, minutes and seconds is known as a simple movement. Common complications include date or day-of-the-week indicators, alarms, chronographs (stopwatches), and automatic winding mechanisms. Complications may be found in any clock, but they are most notable in mechanical watches where the small size makes them difficult to design and assemble. A typical date-display chronograph may have up to 250 parts, while a particularly complex watch may have a thousand or more parts. Watches with several complications are referred to as grandes complications.
Citizen Watch Co., Ltd., also known as the Citizen Group, is an electronics company primarily known for its watches and is the core company of a Japanese global corporate group based in Nishitokyo, Tokyo, Japan. In addition to Citizen brand watches, it is the parent of American watch company Bulova. Beyond watches, Citizen also manufactures calculators, printers, health care devices, and precision CNC machining equipment.
The history of watches began in 16th-century Europe, where watches evolved from portable spring-driven clocks, which first appeared in the 15th century.
Timex Datalink or Timex Data Link is a line of early smartwatches manufactured by Timex and is considered a wristwatch computer. It is the first watch capable of downloading information wirelessly from a computer. As the name implies, datalink watches are capable of data transfer through linking with a computer. The Datalink line was introduced in 1994 and it was co-developed with Microsoft as a wearable alternative to mainstream PDAs with additional attributes such as water resistance, that PDAs lacked, and easy programmability. The watch was demonstrated by Bill Gates on 21 June 1994 in a presentation where he downloaded information from a computer monitor using bars of light and then showed to the audience the downloaded appointments and other data. The early models included models 50, 70, 150 and model 150s. The model numbers indicated the approximate number of phone numbers that could be stored in the watch memory. These early models were, at the time of their introduction, the only watches to bear the Microsoft logo. The watches have been certified by NASA for space travel and have been used by astronauts and cosmonauts in space missions. There had been an evolution over the years as to the number and type of entries that can be stored in the various watch models as well as the mode of data transfer between computer and watch. At the time of its introduction the watch was considered high-tech.
A mechanical watch is a watch that uses a clockwork mechanism to measure the passage of time, as opposed to quartz watches which function using the vibration modes of a piezoelectric quartz tuning fork, or radio watches, which are quartz watches synchronized to an atomic clock via radio waves. A mechanical watch is driven by a mainspring which must be wound either periodically by hand or via a self-winding mechanism. Its force is transmitted through a series of gears to power the balance wheel, a weighted wheel which oscillates back and forth at a constant rate. A device called an escapement releases the watch's wheels to move forward a small amount with each swing of the balance wheel, moving the watch's hands forward at a constant rate. The escapement is what makes the 'ticking' sound which is heard in an operating mechanical watch. Mechanical watches evolved in Europe in the 17th century from spring powered clocks, which appeared in the 15th century.
A chronometer is an extraordinarily accurate mechanical timepiece, with an original focus on the needs of maritime navigation. In Switzerland, timepieces certified by the Contrôle Officiel Suisse des Chronomètres (COSC) may be marked as Certified Chronometer or Officially Certified Chronometer. Outside Switzerland, equivalent bodies, such as the Japan Chronometer Inspection Institute, have in the past certified timepieces to similar standards, although use of the term has not always been strictly controlled.
The quartz crisis (Swiss) or quartz revolution was the advancement in the watchmaking industry caused by the advent of quartz watches in the 1970s and early 1980s, that largely replaced mechanical watches around the world. It caused a significant decline of the Swiss watchmaking industry, which chose to remain focused on traditional mechanical watches, while the majority of the world's watch production shifted to Japanese companies such as Seiko, Citizen and Casio which embraced the new electronic technology. The strategy employed by Swiss makers was to call this revolution a 'crisis' thereby downgrading the advancement from Japanese brands.
Gallet (ˈgæl.eɪ) is a historic Swiss manufacturer of high-end timepieces for professional, military, sports, racing, and aviation use. Gallet is the world's oldest clock making house with history dating back to Humbertus Gallet, a clock maker who became a citizen of Geneva in 1466. It is one of the oldest continuously operating companies in the World. The Gallet & Cie name was officially registered by Julien Gallet (1806–1849) in 1826, who moved the family business from Geneva to La Chaux-de-Fonds, Switzerland. Prior to this date, operations commenced under the name of each of the Gallet family patriarchs.
Quartz clocks and quartz watches are timepieces that use an electronic oscillator regulated by a quartz crystal to keep time. This crystal oscillator creates a signal with very precise frequency, so that quartz clocks and watches are at least an order of magnitude more accurate than mechanical clocks. Generally, some form of digital logic counts the cycles of this signal and provides a numerical time display, usually in units of hours, minutes, and seconds.
The Casio AE-1000W is a quartz digital watch manufactured by Casio, a Japanese electronics company. The watch was introduced in 2010 in the "Youth Series" range of watches designed to attract young buyers. The watch is popular for its many features, including world time, and its low price. The AE-1000W has several other variations as part of the AE-series of watches in the Casio Youth Series.
The Casio CA-53W is a digital calculator watch manufactured by the Japanese electronics company Casio and was introduced in 1988 as a successor to the CA-50. It became famous for its appearance in the American science fiction films Back to the Future Part II (1989) and Back to the Future Part III (1990) and later for appearing in the American TV series Breaking Bad (2008–2013).
Media related to Casio F-91W at Wikimedia Commons| Products |
|  | ||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Other | ||||||||||||||||||||||||
