Harken 40mm Carbo Single Ratchet Block w/Swivel [2608]40mm Carbo Single Ratchet Block with Swivel Carbo Ratchets allow sailors to hand hold loaded lines and offer balance between holding power and controlled easing. 2608, 2609, and 2614 have on off switches. Features: Sheave (mm): 40 mm Sheave (in): 1 9 16 in Maximum line (mm): 10 mm Maximum line (in): 3 8 in Maximum working load (kg): 136 kg Maximum working load (lb): 300 lb