The ISC 200 Series Pulleys are redesigned versions of the popular ISC arborist blocks
Optimized for the forces arborists put on their blocks the new axle and frame interlocking design using heat-treated hardened steel axles means that these pulleys are up to 150% stronger than their predecessors
The Patent Pending SafeLock system is an updated version of the ISC SpringLock design that provides an extremely low profile along with the same quick opening action