Couldn't find anything like this online so I threw one together real quick.

2cm x 100cm strap, 1mm thick, designed to be printed on 220mm x 220mm or larger print bed in TPU or a similar flexible material.

There are no holes pre-positioned for snap buttons, you will have to measure them out and punch them yourself. I recommend any of the myriad "Metal Snap Fastener Button Kit Sets" or similar products you can get for like $7 on amazon, and I would look for size 10mm-15mm buttons.

This strap will not stretch like the elastic ones most people are probably used to, so bear that in mind when measuring.

TPU is a good choice because it is supposedly "body safe," meaning no phthalates leaking into your skin over a prolonged period of time. Obviously if you print it in anything that doesn't flex it won't be a strap, but a rigid spiral of unknown purpose.

I have worn this strap for some time now and have had no issues.