Carbo Air Blocks are 60 per cent stronger and 30 per cent lighter than our Classic blocks. Use the 40 mm Carbo for jib and mainsheet systems on high-performance dinghies and for loaded control lines on small keel boats. The nylon-resin side plates 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 side plates are UV-stabilized with carbon black for maximum protection. Use for: Main/jib sheets, Mainsheet fine-tune, Control lines, Vangs, Cunninghams and Outhauls.