allows either a high-load purchase of 5:1 or 6:1.Low-friction Carbo AirBlocks are lightweight, strong, reliable—and economical. Consistently 30% lighter and 60% stronger than equivalent Classic blocks. The sideplates are UV-stabilized, high-strength resin and designed for small-diameter lines favored by racers. Good for jib and mainsheet systems on high-performance dinghies, and for high-load control lines on small keelboats.Recipient of both the Dame Award and Sail Magazines Freeman-Pittman Award for innovation, this innovative line of blocks turns fiber-reinforced composite construction into a reliable strength-to-weight ratio you can depend on. Companions to the popular Harken Black Magic block line, these small, compact blocks work well with very high working loads for easy trimming.Key FeaturesHigh strength-to-weight ratio blockHarkens most innovative blocks30% lighter, 60% stronger than equivalent conventional blocksSmaller block for jib and mainsheet systems on high-performance dinghiesUse for high-load control lines on small keelboatsStainless steel swivel shackleSheave Diameter: 1 9/16" (40 mm)Max. Line Diameter: 3/8" (10 mm)Max. Working Load (MWL): 1455 lb. (660 kg)Breaking Load: 3050 lb. (1383 kg)Weight: 6 oz. (170 g)Length: 3 11/16" (94 mm)