The DMM Hitch Climber Pulley is designed for rugged use in a work environment and is made with 4 mm thick 2014T6 side plates to enhance durability. All pulleys are riveted and tamper proof, DMM uses high strength nickel chrome molly ground steel spindles, running in pre-lubricated sintered bronze bearings, which are machined after fitting to the pulley sheave to give the smoothest action possible. The Hitch Climber Pulley is intended for arborists and for rescue applications. Recommended rope size up to 1/2" (14mm). All DMM products are rated for fall protection standards only. They are not rated for lifting