40mm Carbo Single Ratchet Block with SwivelCarbo 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 Ø (mm): 40 mm. Sheave Ø (in): 1-9/16 in. Maximum line Ø (mm): 10 mm. Maximum line Ø (in): 3/8 in. Maximum working load (kg): 136 kg. Maximum working load (lb): 300 lb