Single block with front-side shackle. Delrin(tm) sheave ensure smooth operation and high safe working loads. Sheave Dia. 1 7/16", Thickness 3/4" (19mm), Width 1 9/16" (40mm), Length 3 25/32" (96mm), SWL 1000 lbs (410 kg), Weight 2.1oz. (59g), Max Line 7/16" (8mm)