RockyMounts DriveShaft HM 10840RockyMounts DriveShaft HM is a reliable locking hard mount bolt-on system for trucks, SUVs, and trailers. The DriveShaft HM has a flat mounting surface designed for do-it–yourself bolt-on installation and has a unique feature that allows it to easily convert from 15mm to 20mm with the insertion of plastic sleeves. The wide mouth opening allows for easy loading/unloading and provides a strong grip on your bike. Mounting hardware not included but locks and keys are.186135000983