Casio took their legendary F91W, installed adapters, and ran a nato strap through them. The result is the Casio F91WF, where the F stands for “fabric.” I picked one up because the advantage of that fabric strap is longer length. I cannot wear the standard F91W because the band is too small.
So in that light, maybe the F stands for “fat.”
Why don’t I have an F91W
This is the first F91W I have ever owned. Many are surprised that in my 46 years of living I always passed up on the best-selling Casio watch. It’s more than the short band. The F91W is a three button, which I never liked.
Some people may be wondering what the big deal is with three buttons. Look, it’s not like I have an aversion to a certain number of buttons. My gripe is that Casio put the time setting mode in a cycle with the main time, alarm, and stopwatch. In my experience this causes me to accidentally change the time. I don’t notice I have the watch on the time adjustment function rather than the regular display of time.
Having a dedicated fourth button that you need to hold down for a couple seconds to set the time is a must-have feature on my watch!
But I picked up the Casio F91WF just for fun. I’ll try it on and wear it around to see if the three button experience is really as bad as I remember it from the 80’s.
Video Summary
The main ingredient of my unboxing videos is chaos. So the last thing that I want to do type out a summary. I’ll delegate that task to AI. This is the primary reason they’re building more data centers: to summarize my chaotic unboxing videos.
Here is a summary of my video generated by Google’s Gemini AI:
Casio F-91WF Unboxing & Review: The Legendary Digital Watch Gets a Factory Fabric NATO Strap
The Casio F-91W stands as one of the most iconic, widely worn, and recognized digital quartz wristwatches in horological history. In this hands-on unboxing and first impressions review, Jim Kinkade takes a close look at an updated factory variant: the Casio F-91WF-1AF, featuring factory strap adapters and a pass-through fabric NATO-style strap.
Jim puts the watch through its paces, sizing it up with workshop wrenches, comparing it against heavy-duty G-Shock giants, evaluating its hardware, and addressing whether this ultra-thin classic can actually survive on a large wrist.
The New Fabric Pass-Through Strap & Hardware Architecture
The headline update on the F-91WF is its factory-equipped woven fabric canvas band:
- Pass-Through NATO System: Unlike standard F-91W resin bands that mount directly via exposed pins, the F-91WF incorporates factory lug adapters allowing a continuous pass-through fabric strap.
- Spring Bar Protection & “Pins Will Pop”: Traditional cheap resin straps have a notorious tendency to pop their spring bars under tension, resulting in a lost watch. While spring bars are still concealed within the adapters, their tightly shrouded clearance leaves very little room to lever out, offering improved retention.
- Metal Keepers & Buckle: The strap comes equipped with a solid metal buckle along with dual metal keepers—one fixed near the buckle and one floating to tame the excess strap tail.
- Strap Swap Potential: Because the factory adapters accept standard pass-through webbing, users can easily slide out the stock band and thread through longer aftermarket NATO straps.
Sizing, Wrist Fit & The Open-End Wrench Test
Known for his unique workshop method of gauging watch thickness with mechanics’ wrenches rather than digital calipers, Jim measures the F-91WF:
- The 11/32″ Profile: The bare watch case fits snugly inside an 11/32-inch open-end wrench (~8.7 mm), expanding to roughly 3/8-inch when accounting for the pass-through webbing beneath the stainless steel case back.
- The King vs. F-91W Contrast: Placed side-by-side against the massive G-Shock “King” (GX-56BB), the F-91W measures less than half the King’s 11/16-inch slab thickness.
- Big Wrist Compatibility: On an 8.5-inch wrist, the factory strap reaches the very last sizing notch. While it fastens and tucks into both metal keepers, buyers with wrists larger than 8.5 inches will likely need to swap in an extended NATO strap.
- Door Jamb Clearance: Jim highlights that the ultra-slim profile keeps the case hugging flat against the wrist, drastically reducing door frame impacts and snagging compared to oversized tactical watches.
The 3-Button Dilemma vs. 4-Button Casios
While the minimalist counter-culture appeal of the F-91W has made it an enduring internet favorite, its basic 3-button module has practical drawbacks:
- Accidental Time Setting: Because the bottom-left “Mode” button directly enters the flashing time-setting screen after cycling past the daily alarm and 1/100th-second stopwatch, it is very easy to inadvertently alter the time while glancing through functions.
- The Case for 4-Button Casios: Jim argues that models featuring a dedicated fourth, recessed “Adjust” button—such as the Casio AE-1500WH, AE-1600, or TRT-110—prevent accidental time adjustments and provide greater peace of mind for scheduled work shifts.
Legibility, Illumination & Durability Expectations
- Old-School LCD Clarity: Looking through a single, clean acrylic crystal layer gives the F-91W crisp digit contrast and sharp viewing angles, avoiding the polarizing haze seen on multi-layer dual LCDs (like the Mudman GW-9500).
- Green LED Backlight: The watch retains its vintage single green LED located on the left flank of the display. While functional for a quick dark check, it preserves the retro feel over modern electroluminescent (EL) or full-face LED arrays.
- Flat Acrylic Crystal vs. Raised Bezels: Unlike G-Shock cases with crenellated resin bezels designed to absorb blows before contacting the glass, the F-91W’s crystal sits flush and exposed. While susceptible to scuffs under heavy mechanical work, its rock-bottom price point makes it an easily replaceable beater.
- Water Resistance: Rated for standard water resistance (splash/rain proof) with a dependable 7-year battery life, Jim notes that full submersion and impact durability will soon face the ultimate trial: a meeting with the shop’s Watch Bopper 5000.
The Verdict
The Casio F-91WF takes an undisputed budget classic and fixes its biggest structural liability by adding durable pass-through strap adapters. For fans seeking ultra-lightweight, no-fuss digital timekeeping that slips under work gloves and sleeves with zero bulk, it remains the ultimate anti-smartwatch statement.
Conclusion
The AI was really impressed that I used open ended wrenches instead of calipers to size up my watches. I think it’s a good, quick way to measure the thickness of a watch. It’s funny that the King is twice the size of the F91WF. The King was 11/16″ and the F91WF was 11/32.”
The European mind cannot comprehend.