Foot Block. Computer machined block finished in hardcoat anodized black for durability. Torlon(tm) rollers and Delrin(tm) ball bearings ensure a low-friction aluminum sheave that will handle high loads. Top cheek will swivel out of place for easy installation. Flushing holes in each cheek allow easy flushing. Safe Working Load 2800lbs (1270kg), Weight 7.2oz(204gm), Max. Line 1/2" (12mm), Sheave Diameter 2.6" (66mm), Length 4.5" (114mm) Width 3.2" (82mm). Requires (4) 1/4" (6mm) Flat Head Fasteners.