Harken 2608 Carbo Ratchet Block 40mm allows sailors to hand-hold loaded lines and offer balance between holding power and controlled easing. This single swivel block is ideal for jib sheets and spinnakers where size and weight are critical. The nylon-resin side plates of the Harken block are densely packed with long-glass fibers for a compact block with a high strength-to-weight ratio. Aluminum sheaves are Hardkote anodized for strength and corrosion resistance. Eight facets hold line securely. Ball bearings, side plates, and sheave are UV-stabilized with carbon black for maximum protection.