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 A~ (mm): 40 mmSheave A~ (in): 1-9/16 inMaximum line A~ (mm): 8 mmMaximum line A~ (in): 5/16 inMaximum working load (kg): 150 kgMaximum working load (lb): 330 lb