Single block with aluminum cheeks and ball bearing sheave. Delrin(tm) ball bearing sheave ensures low-friction operation. Swivel head may be locked in place to avoid twist. Sheave Dia. 2" (51mm), Thickness 15/16" (24mm), Width 2 1/8" (54mm), Length 4 13/32" (112mm), SWL 1500 lbs. (680kg), Weight 5oz. (142g), Max Line 7/16" (11mm)