505-20 fits Isomat mast collar with a pin diameter of .510". Stainless steel cheeks and Delrin(tm) sheave ensure smooth operation and high safe working load. Sheave Dia. 2" (51 mm), Max Line 7/16" (11 mm), Pin dia. .510 Hole, L 3-3/32" (79 mm), W 2-1/8" (54 mm), T 13/16" (21 mm), SWL 1750 lbs (795 kg), Weight 7.1 oz (201 g)