Forerunner 305 Bicycle Headset Mount

fr305.stl - For use while keeping the wristband on the watch (RECOMMENDED/SAFEST).
fr305nostrap.stl - Wristband removed and uses the pins to "click" the watch in place.

I suggest printing with support and with one of the longer sides pointing up/down (as in the model preview above).

If you decide to go with the "no strap"-mount, please check that the watch sits firmly in the mount before riding.