About: Robertson Mountaineering - SR-71 Tandem Zip Pulley w/ Backup Ears
- The Robertson SR-71 is a fully rebuildable platform highly recommended for commercial applications.
- The sheaves are case hardened to 56-58 Rockwell and spin on sealed ball bearings.
- The axles are made of 304 steel and are time tested, proving outstanding durability and structural design for 25 years.
- Side plates are .105-inch thick, made of 304 stainless steel for superior strength.
- Cable Sizes:
- 5065-E: Pulley is designed to move a person down a 3/8 - 1/2 cable safely at speeds up to 65 mph.
- 5067-E: Pulley is designed to move a person down a 5/8 - 3/4 cable safely at speeds up to 65 mph.
- Length: 5 5/8" (142.9 mm)
- Height: 5 1/16" (128.6 mm)
- Minimum 3 sigma breaking strength (3σ MBS) of not less than 36 kN (8,093 lbs)
- Independent test rated to 19,000 Lbs.
- NFPA 1983-2012 Section 126.96.36.199 Pulley Performance Requirements- General Use
- Tested to NFPA 1938-2012 Class G, exceeds ANSI and OSHA standards