What to do with your old WHOOP 4.0 bands

The bad news first

A WHOOP 4.0 band does not mount on a WHOOP 5.0 or a WHOOP MG. The connector and the clasp changed shape, it is not a question of size, and no adapter exists. That is final.

If you have just moved to the 5.0, your collection of 4.0 bands does not come with you. Better to know before hunting for a solution that does not exist.

What remains possible

Give them away. The most useful option. WHOOP 4.0 is still very widely used, and a set of bands in good condition is a real service to a club or a gym.

Sell them on. A second-hand market for 4.0 accessories still exists, precisely because the model is still in circulation.

Keep them for something else. A woven band with its clip is still an adjustable strap: enough to hold a coiled cable, a pair of glasses, or something in a bag.

What does not work

All the workarounds that circulate — forcing the module, filing the housing, using a 3D-printed spacer — lead to the same result: a device that holds badly, so a sensor that shifts, so false readings. Mostly you risk losing an expensive device inside a sleeve.

What to remember for the next purchase

Compatibility takes ten seconds to check in the WHOOP app, under device settings. A listing that says “fits all WHOOP” is either mistaken or misleading you. See: 4.0 or 5.0?

Rebuilding a collection

If you owned several, there was a good reason: rotation is what makes a band last. Apply the same principle rather than starting again with one. See: how many bands.

Our bands are built for WHOOP 5.0 and WHOOP MG: plain colourways, printed models and charms.

Starting over

If the drawer yields nothing worth keeping, the safe restart is three colours that do not date: Jet, Slate, Already Late Black. None of the three argues with what you already wear.