AirTag dog collar holder for 20 mm collars
A screw-closed AirTag holder that slides onto a 20 mm dog collar and sits flat against the neck, so the tag does not dangle, jingle or snag in bushes. The AirTag (31.9 mm diameter, 8 mm thick) sits in a 32.2 mm pocket 8.3 mm deep, the lid closes with two M2.5 screws, and the back has a 21 x 3 mm strap slot with rounded edges. The body is 42 x 42 x 13 mm with 2 mm walls, a small speaker opening on the lid, and prints in two flat halves.
Collar widths run from 15 to 38 mm, so a downloaded holder is either too tight to fit or slides around. In SpeakCAD you give the collar width and thickness, preview the holder free in the browser, add a name plate or a cat-size version in the chat, then download the STL and print it in PETG or TPU.
Model a 42 x 42 x 13 mm AirTag collar holder with a 32.2 mm diameter, 8.3 mm deep pocket, a lid fixed by two M2.5 screws, a 21 x 3 mm through slot on the back for a 20 mm collar with 1 mm fillets, a 10 mm speaker opening and 2 mm walls.