40mm Carbo Single Fixed BlockLow-friction Carbo Air blocks are lightweight, strong, reliable-and affordable. Companions to the popular Harken Black Magic block line, these small, compact blocks have very high working loads for safe, easy trimming. 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): 220 kg Maximum working load (lb): 485 lb