10 Series Single Block with Stainless Steel cheeks and Aluminum "universal circuit" ball bearing sheave. Aluminum sheave run on Delrin(tm) ball bearings for a very strong yet low-friction sheave. Stainless Steel D shackle run on a swivel head that may be locked in plate to avoid line twist. Bolted construction allows for easy maintainence. Sheave Dia. 3-1/4" (83mm), Thickness 1-7/32"(31mm), Width 3-1/4" (83mm), Length 6-19/32" (167mm), SWL 3750 lbs (1750kg), Weight 1 lb 11 oz (765g), Max Line 5/8" (16mm)