Just a basic strap mount for a GoPro. Both clip-in and screw versions are on here. The screw version takes a standard M5 nut. I test printed a LOT of these things to get the dimensions just right. These hold my GoPros great. I'd recommend clip over screw as the screw pillars are weaker than the clip walls.
UPDATE: Cura sliced the screw mount oddly in back. Re-uploaded a better version.
I like these in PETG as it's durable and flexes a bit before it would snap. Need to use supports and I'd try to adjust settings so supports fill in the nut holder. Otherwise it tends to sag and you'll need to auger it out a bit.