Fiddle block with anodized aluminum cheeks and swivel snap shackle. Swivel may be locked in place to avoid twist. Snap shackle allows for a variety of applications. Delrin(tm) sheaves ensure smooth operation and high safe working loads. Works with either 504-51, 504-75 or 504-76 for a 4:1 purchase. Sheave Dia. 2" (51mm), Thickness 15/16" (24mm), Width 2 3/8" (60mm), Length 6 29/32" (175mm), SWL 1750 lbs. (795kg), Weight 7.6oz (215g), Max Line 7/16" (11mm)