The Robertson Cobra Cable Pulley represents the most advanced design work using state of the art engineering techniques to build the safest and finest trolley for the ropes course industry. The 304 stainless steel frame is .101 thick for superior strength and trouble free use. It is assembled using machined 304 stainless axles which gives the Cobra unparalleled structural integrity. The Cobra uses two additional back-up axles for safety. These two extra axles also gives the Cobra superior stability. The sheaves are 2" in diameter and case hardened to 56-58 Rockwell and ride on sealed ball bearings to provide excellent wear characteristics in challenging outdoor environments. Built for 3/8" and 1/2" diameter cable. Second safety tether hook-up point provided on rear of pulley. Other attachment points provided for haul or drag lines make this pulley the ultimate in rescue operations.