Stainless Steel Single Block with UC Sheave 08-05-UC8 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. 2 3 8" (60mm), Thickness 1 3 32" (28mm), Width 2 3 8" (60mm), Length 5 5 8" (143mm), SWL 2750 lbs