News / Wearables / 3D Printing / Updated June 28, 2026

Google just handed Fitbit Air owners the CAD files to print their own bands

The spec pack is the easy part. The thing strapped to your wrist all day is what actually deserves your attention.

If you bought a Fitbit Air partly because it's small, cheap and gets out of your way, Google just gave you one more reason to keep it. The company published 2D CAD drawings and a set of guidelines that let you design a custom accessory band in your CAD software of choice and 3D print it to fit the tracker precisely — without covering the sensors or otherwise hurting how it works.

It's a genuinely good move. Official dimensions mean you're not reverse-engineering a band from calipers and guesswork. But most of the coverage stops at "Google released CAD files, go nuts." The interesting part — and the part that actually decides whether your band is comfortable, safe and worth wearing — is everything Google put around those drawings. So that's where we'll spend our time.

Quick context on the tracker itself: the Fitbit Air is Google's lightest fitness tracker, sells for about $100, and has no screen by design — the idea being it tracks your fitness without becoming one more thing buzzing for attention. That minimalism is exactly why a custom band makes sense. The hardware is deliberately plain; the band is where personality lives.

What Google actually released

The drawings cover the two geometries that matter for a band: the pebble (the tracker module) and the sleeve (the part of the band that captures it). That's the interface you have to nail. Everything else — the strap, the closure, the styling — is yours to invent.

But a drawing of the pebble is a starting point, not a finished model. Google supplies the dimensions; you still have to build the 3D model from them in your CAD tool and respect the published specifications and tolerances. Get those wrong and the band either won't seat, will pop off mid-run, or will press on something it shouldn't. The guidelines also include the requirements that are easy to skim past: material rules, chemical limits, environmental standards and testing expectations.

This thing touches your skin all day

Here's the line in Google's own guidance that deserves a highlighter: the material should be friendly to the skin to prevent irritation or allergic reactions. That sounds obvious until you remember how most hobby filament gets made. A spool of generic flexible filament off a marketplace is formulated to print well and look good — not to sit against sweaty skin for sixteen hours a day, every day.

Google clearly anticipated this, which is why the document goes past "make it skin-friendly" into specific chemical limits and testing requirements. Treat those as the floor, not a formality. A band you'll wear daily is one of the few printed objects where the material's skin-contact profile matters more than how it looks coming off the plate.

Which material actually works

For a band you want flex without floppiness, so the realistic candidate is TPU (thermoplastic polyurethane) — the flexible filament family that already dominates phone cases, grips, gaskets and wearables. Within TPU, hardness is the dial that matters most:

Shore 95A is the universal sweet spot — firm enough to hold a buckle and keeper-loop geometry, flexible enough to wrap a wrist comfortably. Shore 85A is softer and more rubber-like, which feels nicer against skin but is fussier to print and can deform under a tight closure. Most people end up at 95A for the structural parts and reserve softer grades for contact surfaces if they want them. Our full breakdown of every filament — including where TPU shines and where it bites back — lives in the 2026 filament guide.

Whatever brand you choose, look for documented skin-contact or biocompatibility information from the manufacturer and favor materials that line up with the chemical limits Google specifies. If a filament's datasheet says nothing about skin contact, treat that silence as a "no" for a daily-wear band — print a prototype in it to check fit, then switch to a known-good material for the one you'll actually wear.

How to actually print one

The workflow is straightforward once the material question is settled. The hardware caveat: flexible filament punishes the wrong setup, so a couple of steps below aren't optional.

1. Get Google's CAD spec pack

   Download the official 2D drawings and read the full guidelines, not just the dimensions. The chemical limits and testing notes are part of the spec.

2. Model the band from the published dimensions

   Build the sleeve and strap in Fusion, Onshape, FreeCAD or whatever you run. Honor the tolerances exactly, and keep the optical-sensor window clear.

3. Choose a skin-friendly flexible filament

   A TPU with manufacturer skin-contact data, matched to Google's chemical limits. Prototype fit in anything; wear-test only in a known-good material.

4. Print on a direct-drive machine — and bypass the AMS

   Bowden setups buckle soft TPU. Direct drive is strongly preferred, and flexibles should feed from an external spool rather than through an automatic changer. (More on why in our Bambu AMS guide.)

5. Deburr, fit-check, then wear-test

   Knock down any layer ridges on the skin side, confirm the pebble seats and releases cleanly, and do a short wear test before committing to all-day use.

One San Diego-specific gotcha

TPU is hygroscopic — it drinks moisture out of the air — and coastal San Diego humidity is exactly the enemy. Wet flexible filament prints with surface fuzz, stringing and weak layers, which is the last thing you want on a part that bends thousands of times on your wrist. Dry your spool before a band print and store it sealed. If your prints are coming out rough no matter the settings, moisture is the usual culprit.

You're allowed to sell them

Here's the part with real upside: Google says you're free to sell your custom bands, as long as you follow the company's marketing rules and brand guidelines. For anyone already running a small print operation, that turns a published spec sheet into a product line — themed bands, durable replacements, accessibility-minded closures, niche colorways the official lineup will never bother with.

Read Google's marketing and brand terms carefully before you list anything, and lean on the same skin-contact discipline from above — a band you sell carries more responsibility than one you print for yourself. This is the same pattern we wrote about with the foldable iPhone: the moment accurate dimensions go public, a 3D printer turns into an accessory business.

Don't own a printer — or don't want to fight TPU?

Printing flexibles well is its own skill, and skin-contact parts raise the stakes. If you'd rather not buy a machine to make one band, you've got options: many public libraries have printers you can use, an affordable flexible-capable machine is within reach (see our budget multicolor printer roundup), or you can hand the whole thing off.

That last one is us. Dreaming3D runs FDM and resin printing here in Carmel Valley, San Diego — bring us Google's specs and your idea, and we'll model and print a band in an appropriate skin-friendly material, including small batches if you're planning to sell. We also do mobile printer repair across San Diego County and ship work statewide.

Common questions

Fitbit, Fitbit Air and Google are trademarks of their respective owners and are referenced here for descriptive purposes. Dreaming3D is independent and not affiliated with or endorsed by Google. Specifications, pricing and program terms are described as of June 28, 2026 and may change — verify current details and Google's official guidelines before designing, printing or selling.