74-77 single sheave control block with removable becket for pre-spliced line. Hardcoat anodized aluminum base fits on Schaefer 1-1/2" traveler track. Features Schaefer 5 series ball bearing sheave for low-friction and reliability. Length = 5-1/4” (133mm), Width = 2-1/16” (52mm), Thickness = 1-15/32” (38mm), Weight = 14oz.(379g)