This model replaces the chrome cap of the BMW coupe E92 extender arm with a hook that grabs the seatbelt successfully much more often than the original design. Designed to be a near perfect fit with the OEM shape. I recommend printing in ASA or ABS for the high temperatures in a car. The OEM piece easily comes off with a pry tool, then you can attach the 3d printed models with a strong double sided adhesive ( Confirm normal seat, belt and presenter movement and keep the printed part outside the restraint load path.
