I wouldn't trust this in anything but PC or nylon or something along those lines. I printed this out of PC. The stemcap was tested and held over 11Nm of torque which is more than should ever be applied. I've tested it on a few mountain bike rides and feel very comfortable with my phone mounted.
Print with 1-2 perimeter layers and 100% rectilinear infill layers for maximum strength.
The author marked this model as their own original creation.