Zip Line Pulley- The "COBRA" cable pulley zip line trolley represents the most advanced design work using state of the art engineering techniques to build the safest and finest zip line trolley for the ropes course industry. The Zip line trolley frame is a two piece design with two back-up axles which when used with the back-up safety slot at the rear of the zip trolley adds two levels of security to the user in case of catastrophic failure. The 304 stainless steel frame is .105 thick for superior strength and trouble free use on zip lines and canopy tours. The zip trolley sheaves are Stainless Steel and spin on sealed ball bearings to provide excellent wear characteristics in challenging outdoor environments. The 304 stainless steel axles are time tested performers and have been in use on zip lines and canopy tours for over 25 years. Built for cable up to ½" Diameter. Independently tested to 11,000 lbs. Exceeds A.N.S.I., OSHA, and NFPA Class G StandardNOW AVAILABLE FOR 5/8" and 3/4" CABLE!