303-50 Halyard/Control block. Delrin(tm) sheave ensures smooth operation and high strength. Stainless base and Anodized aluminum cheeks provide a solid platform. Sheave Dia. 1-7/16, (37 mm), Max Wire 7/16, (11 mm), Jaw Opening 1-3/4, (44 mm), Pin. Dia. 1-5/8, (41 mm), Length 1-31/32, (50 mm), Width 19/32, (15 mm), T (4), #10 RH (5 mm), C/C Length 1-5/32, (29 mm), C/C Across 1-5/16, (33 mm), SWL 1000 lbs. (454 kg)