Fiddle block with becket, cam cleat and snap shackle attachment. Swivel snap shackle may be locked in place to avoid twist. Delrin(tm) sheaves ensure smooth operation and high safe working load. Fast Entry cam cleat allows for easy line engagement. Works with 504-49 for a 4:1 purchase or 504-45. Sheave Dia. 2" (51mm), Thickness 2 5/16" (58mm), Width 3 7/32" (82mm), Length 6 7/8" (174mm), SWL 1750 lbs. (795kg), Weight 12oz. (340g), Max Line 7/16" (11mm)