The Robertson SR-71 Tandem Zip Pulley is a cable pulley that 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.

• 304 stainless steel frame is .101 thick for superior strength and trouble free use
• Assembled using machined 304 stainless axles which give unparalleled structural integrity
• Additional back-up axle for safety, produces superior stability
• Sheaves are 2" in diameter, 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