Half-Moon hinged base block. Heavy duty Stainless Steel cage and base ensure reliability. SS Springs keep block upright. Aluminum UC sheave features nomex(tm)/Teflon(tm) bearing and Delrin(tm) ball bearings for a low-friction high strength sheave. Sheave Dia. 2-3/8" (60 mm), Max Line 5/8" (16 mm), Length 4" (102 mm), Width 1-3/4" (44 mm), Height 4" (102 mm), Bearing Height 1-5/8" (41 mm), Fasteners (4), 1/4" RH (6 mm), C/C 3" (76 mm), SWL 3000 lbs. (1361 kg), Weight 15 oz. (425 g)