40mm/29mm Carbo Traveler 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): 8 mm Maximum line ; (in): 5/16 in Maximum working load (kg): 150 kg Maximum working load (lb): 330 lb