The original Pedro's Chain Keeper has been a favorite in the wash buckets of mechanics for decades. The new Pro Chain Keeper carries this heritage forward to new levels featuring one-handed installation, shifting across all gears, professional duty stainless-steel and aluminum construction, a heavy-duty solvent resistant plastic pulley, and 12mm thru axle compatibility. Takes place of rear wheel providing tension on chain to protect the frame when rear wheel is removed for cleaning, storage, or transport Allows full forward or backward rotation of drivetrain and shifting through full range of gears Quick and easy one-handed installation on standard QR style dropouts and removable pulley wheel works directly on 12mm thru axles Professional grade stainless-steel, aluminum, and solvent resistant plastic components ready for daily life in the wash bucket