Pulpit Furling Lead Spring Loaded Block - 1" Ball BearingThe Stainless Steel spring guarantees maximum support for the block. Delrin™ ball bearing sheave ensures low-friction lead for your furling line.Specifications:1" (25mm) stanchionsLength 4-11/32" (111mm)Width 1-9/16"(40mm)Safe Working Load 1000 lbs (450kg)Weight 4 oz (113g)Max line size 7/16" (11mm)Sheave diameter 1-7/16" (37mm)