M82-62 Stand Up Spring Block. Machined anodized aluminum cheeks with 316 Stainless Steel spring and base. Anodized aluminum sheave runs on Torlon(tm) rollers and Delrin(tm) ball bearings for a low-friction strong block. Order backing plate 97-37 sold separately. Safe Working Load 5000 lbs (2270kg), Weight 19.2oz (544gm), Max. Line 5/8"" (16mm), Sheave Diameter 3.2" (82mm), Base Diameter 2 7/8" (73mm), Requires (4) 5/16" Flat Head Fasteners.