506-60 Ball Bearing Halyard/Control Block. Delrin(tm) ball bearing sheave ensures low-friction yet high strength. Anodized aluminum cheeks with Stainless steel base provide a solid platform. Ball bearing sheave is ideal for control lines under regular adjustment. Sheave Dia. 2, (51 mm), Max Line 7/16, (11 mm), Jaw Opening 2-9/32, (58 mm), Pin. Dia. 1-5/16, (49 mm), Length 2-9/16, (65mm), Width 5/8, (16 mm), T (4), #10 RH (5 mm), C/C Length 1-21/32, (42 mm), C/C Across 1-13/32, (35 mm), SWL 1500 lbs. (680 kg)