Single block with front-side shackle. Delrin(tm) sheave on plain bearing ensures smooth operation and high static load safe working loads. Sheave Dia. 1 1/16" (27mm), Thickness 19/32" (15mm), Width 1 3/16" (30mm), Length 3 15/32" (88mm), SWL 900 lbs, Weight 1.75 oz (50g), Max Line 5/16"(8mm)