Core Block are a true all round solution. A tuned 2-stage bearing system provides excellent performance across the full working load range with an integrated thrust bearing feature and the resilience to handle high dynamic or static loads. Acetal sheave, alloy cheeks and stainless fixings complete the durable package. For reliability and a long service life, these blocks are the right choice for sheets, halyards and control line applications for cruising and racing. Sheave (in.): 3 MWL (lb.): 3300* BL (lb.): 6600* Weight (oz.): 18.7*Full block rated load can only be achieved with uniformly distributed load across full length of clevis pin. ie. 14mm (9/16x9D) diameter mast collar post or 14mm (9/16x9D) wide mast collar plate/tang.