This is a bayonet wrist strap mount for the CycleOps Joule GPS data logger. We use this in our research to track power output and other telemetry from athlete training sessions. We use the Joule GPS in combination with the PowerCal ECG chest strap for Running sessions, and with the PowerTap rear hub attached to one of our prototype bikes for Bionic Running sessions. Printed in nylon, it is held snugly in place with a firm twisting lock - see instructions.
I printed this in nylon, and used chunky rubber wrist straps intended for a diving watch. The wrist strap pins are made from lengths of 1.75mm nylon fused in place with a soldering iron.