The RP145 steel rigging block from CMI was designed for use by professional arborists in false crotch systems to help save wear and tear on bull ropes. Upper bushing maximizes sling strength and wide sideplates protect the rope from contact with rough bark. The lower sheave will accept bull ropes up to 3/4″ diameter. Fabricated from stainless steel for lasting durability in outdoor conditions. Made in the USA.