This is a dummy quick release for a Trimble R10 RTK head. It's designed to take the place of the base station quick release, freeing up a real quick release for a second rover mount. It threads on to a standard 5/8x11 tripod thread, which is used for OEM quick releases. It has symmetrical keying that doesn't match the original, but this just means it can flip 180 degrees if necessary, unlike the original. If your printer's perfectly calibrated, the model should be the exact height of the original (50mm to the shoulder). My printer added about a mm to that.