Single block with becket and swivel shackle.    Anodized aluminum cheeks protect the Delrin (TM) sheave ensuring a reliable unit.  Sheave Dia. 1 7/16", Thickness 3/4" (19mm), Width 1 9/16" (40mm), Length 4 1/2" (114mm), SWL 1000 lbs (410 kg), Weight 2.8oz. (79g), Max Line 7/16" (11mm)