When I say this is the most retro digital watch Casio has released in almost 34 years, I'm not kidding. The F-84 has perfect mid-1980s digital styling. It has the older thinner model text, the "Lithium" word to promote the fact it has a lithium battery, and the alarm graphic right below that to promote the fact it has an alarm function.

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 mode button lets you switch between the alarm, stopwatch, and timekeeping modes. Both the alarm and stopwatch are easy to use, though it may take a few uses for the button layout to become second nature.Japanese Domestic Market (JDM) model. Uses the same 593 module, but the case's design is more similar to the older F-28W and F-87W. It has lugs instead of an embedded strap. Also, this is a very reserved design. The F-91W and W59 are slightly "loud" in appearance. Not the F-84W. It's very simple and pleasant to view. 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] James Ball (April 25, 2011). "Guantánamo Bay files: Casio wristwatch 'the sign of al-Qaida' ". The Guardian. London.

If you’re familiar with the F-91W, then you’re familiar with the F-84W. They’re functionally identical, and you’re not getting any extra or new features here. As you’d expect, the F-84W is incredibly small and thin even for a digital watch. This thing seems to be tailor-made for small-wristed wearers. Guantánamo files: How interrogators were told to spot al-Qaida and Taliban members". the Guardian. April 25, 2011 . Retrieved April 10, 2019.

Another bonus of having a JDM watch strapped to your wrist is that you’re more likely to attract the right kind of attention. Those who know, know. Those who don’t, won’t. It’s as simple as that. Pop a Rolex on your wrist and you’re likely to attract ALL kinds of attention. Even if you don’t use the alarm or stopwatch, you’ll still make use of the main display that gives you everything you need. You have the time, day, and date all right there. Casio F84W watch To further ram home the point that the Casio F-84W is the more delicate model, the resin strap is cut differently. The third to last hole was the max for my six-inch wrist. With the ’91’ however, the fifth to last hole was where I called it. Aufranc (CNXSoft), Jean-Luc (January 11, 2022). "Microchip SAM L22 board makes Casio F-91W watch more customizable (Crowdfunding) - CNX Software". CNX Software - Embedded Systems News . Retrieved October 4, 2023.

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. Sensor Watch — an unofficial open-source hardware circuit board replacement for original F-91W and A158W watches, based on ARM Cortex M0+ microchip with various additional sensors. [27] [28] [29] [30] [31] [32] [33] [34] Interestingly, the light, mode, and alarm buttons on the F-84W are labeled vertically. This saves space and makes the dial look less crowded than the F-91W (which uses horizontal inscriptions).I have a Casio F-28W. Mine is in fairly good shape, but the resin strap crumbled apart years ago, hence the NATO strap. I did the same with the F-84W since I know that strap would suffer the same fate at some point. Casio digital watches have been around for decades, and they’re some of the most popular watches on the market. They’re cheap, reliable, and well-designed. The right button, labeled "Alarm On-Off/24hr", is the function button: when used, it starts and stops the stopwatch, changes the settings currently being adjusted, or switches between the 12- and 24-hour modes, depending on what mode the watch is currently in. Pressing all three buttons at the same time will fill all the cells on the LCD until any button is pressed again. [10] You can really tell when you look at the text on the dial. The fonts are straight out of the mid-80s, and there’s a “Lithium” inscription that doesn’t appear on the F-91W.