Carbo AirBlocks® are 60% stronger and 30% lighter than our Classic blocks. The nylon-resin sideplates are densely packed with long-glass fibers for a compact block with a high strength-to-weight ratio. Sheaves spin on high-load ball bearings with fitted races for low-friction operation. Ball bearings, sheave, and sideplates are UV-stabilized with carbon black for maximum protection.Use 40 mm Carbo for jib and mainsheet systems on high-performance dinghies and for loaded control lines on small keelboats.Use for:Main/jib sheetsMainsheet fine-tuneControl linesVangsCunninghamsOuthauls