PIV CA-53W
The CA-53W is Casio's calculator watch, reissued with a personality nobody else is selling. Punch numbers on your wrist, then slide your own Fitbit Air pebble into the holder under the band to track heart rate, sleep and steps — the tech underneath doesn't have to match the tech on top.
What buyers say
The F-91W looks vintage Casio on the wrist, but it is tracking my steps, heart rate and sleep. My friends have no idea there is a Fitbit sensor in it.
I love the retro look, the design and the overall quality. Got this as a gift for my boyfriend, and he absolutely loves it.
Order
Pick your model, then pay securely on Stripe.
You bring your own Fitbit Air pebble. not included
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FAQs
What comes with your order?
The watch and the PIV nylon band with the pebble holder, already fitted together. Nothing to assemble, so you can take it out and put it on. The original Casio straps come in the box too, so you can always put the watch back to stock.
Do I need my own Fitbit Air?
Yes. The sensor pebble is the one part we do not ship. You lift it out of the Fitbit band you already own and slide it into the PIV holder. It pops in and out in seconds, so you can move it back whenever you like.
Does the tracking still work the same?
Fully. Heart rate, sleep and steps all sync through Google Fit exactly as before. Nothing changes on the software side. You are just wearing the pebble somewhere better looking.
Will it fit my wrist?
It fits wrists from 14.5 to 22cm (5.7 to 8.6 inches), which covers most people. The hook-and-loop closure adjusts anywhere in that range in a couple of seconds. No holes, and no size to pick at checkout.
What is the band made of?
Double-layer woven nylon over a soft cotton weave: light, breathable, and closer to a sport loop than a stiff military nylon. It is one continuous piece that passes under the watch, so there is no hardware sitting against your wrist.
Can I wash it?
Yes. The colour is permanent ink and will not fade, so you can wash the band whenever it needs it. It is built for sweat and daily wear.
Do I need tools to change it?
Not for the PIV band. It sits on quick-release spring bars, so you slide the knob with your finger and it comes off. Swapping it between watches takes seconds.
Taking the original Casio strap off is the fiddly part, since those are not quick-release. That needs basic watch tools, or household ones will do: a pair of pliers and a pin is enough. Your order arrives with the PIV band already fitted, so you only run into this if you decide to go back to stock.
Which watches does the band fit?
Two things have to be true: the lug width has to match, and the case has to be flat and open where the band meets it. A flat one-piece band on quick-release bars needs clean, exposed lugs. On a round case, a hooded lug or a wide flared shoulder, it will not sit right and you may not be able to get it off again.
Casio F-91W · F-93W · F-94WA · F-105W · F-106W · W-59
Casio CA-53W · CA-61W · FT-100W · W-520U · W-720 · W-741 · WL-100 · MAP-100
Will not fit. Hooded-lug models, where the case overhangs the lugs, which includes the Casio A168 and A169. Round watches with downward-curving lugs: Seiko SNK, Orient Bambino, Timex Marlin, Casio MDV-106 and the MTP dress line. The Casio AE-1200 "Royale" family (AE-1300, AE-1000W, AQ-S810W, SGW-300/400/500H, MRW-200H, W-800H, W-216H, F-108WH), which is 18mm at the lugs but flares to 25.5mm at the shoulders. The W-96H, which uses screws rather than spring bars. And G-Shocks, which use proprietary integrated bands.
Checking your own watch. Measure the gap between the lugs. That is your width. Then look at it side-on: the lugs should be fully exposed with nothing overhanging them, the case flat-backed and squared off, and the shoulders no more than about 4mm wider than the lug gap.
How long does shipping take?
Watches are built to order and ship in 7 to 10 business days. The band on its own ships in 3 to 5. US shipping is free on every order.
Do you ship outside the US?
Not yet. US orders only for now.
What if something is wrong with my order?
If it arrives damaged or is not what you ordered, email hello@pivhq.com and we will make it right. Beyond that, all sales are final, because each piece is built to order by a small team.