Harken 40mm Carbo Single Ratchet Block w/Swivel Becket [2609]40mm Carbo Single Ratchet Block with Swivel & Becket 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