RockyMounts BrassKnuckles Non-corrosive aluminum construction Form-fitting mounting hardware fits all crossbars (RockyMounts Ouray, Thule square, Yakima round, Aero Blade, Whisp bar, Rhino rack, and factory) Ergonomic Brass Knuckles handle fits your hand like a glove No frame contact, easy installation and adjustment (driver side and passenger side) Fat bike compatible with RockyMounts Fattie Adapter. Fits all bikes 20" - 29" wheels (except with front fender)