Double block with becket and anodized aluminum cheeks. Works with 504-35 for a 4:1 purchase. Delrin(tm) sheaves ensure smooth operation with high safe working load. Sheave Dia. 2" (51mm), Thickness 1-21/32" (42mm), Width 2-1/8" (54mm), Length 6-3/16" (157mm), SWL 1750 lbs. (795kg), Weight 9.1oz (258g), Max Line 7/16" (11mm)