Product Description: The Piston Pro features some of the same great features as The Piston Pro X minus a few bells and whistles. Features like all metal construction, One Tap hydro-pneumatic tire arms that make no contact on the bike frame, and tool-free wheel chock slides. Features: All metal construction One Tap hydro-pneumatic tire arms No frame contact Patented Fast Fit tool-free wheel chock system Patented Pedal Pivot Patented Flat Lock Hitch Cam for 2", ball cam for 1.25"