ISC Alloy Arborist Block 16mm (5/8"). 

The RP051 from ISC is a cast aluminum block made from high tech aluminum alloy. It is incredibly light, but strong. Aluminum alloy bushings and sheaves are supported by stainless steel axles. Spring lock captive bushings are easily accessed by a quick-twist nob. Sheave is supported by a sintered bronze bushing. Side plates are broad enough to protect lines during use and painted with a powder coated finish.

The design is compact and the unique upper sheave design is quick to open & close and secures easily, plus it eliminates the chance of dropping a sheave. The side plates are thick aluminum and powder coating to enhance the durable life of the block. Strong and durable. 

MBS: 100KN.

WLL: 20KN.