Fiddle block with swivel shackle, cam cleat and becket. Works with 303-45 for a 4:1 purchase. Delrin(tm) sheaves ensure smooth operation and high safe working load. Fast entry cam cleat allows for easy line engagement. Sheave Dia. 1 7/16", Thickness 2 5/16" (59mm), Width 3 1/4" (83mm), Length 6 7/32" (158mm), SWL 1000 lbs (410 kg), Weight 9.6oz. (272g), Max Line 7/16" (11mm)