RP145 CMI Arborist BlockNew from CMI this arborist block with zinc-plated steel sideplates will handle up to 3/4″ lines on a 2-3/4″ aluminum sheave. The sheave rides on bushings around a stainless steel axle. Specifications:Min breaking strength: 25,000 lbs.Weight: 3.65 lbs.Dimensions: 6.5″ x 4.0″