High strength engineering plastic used in the sideplates, sheave and balls allows us to make blocks 60% stronger and 30% lighter than our classic blocks. Use Carbo AirBlocks with hi-tech lines for jib and mainsheet systems on high performance dinghes or for control lines on keel boats. A comprehensive instruction manual details the many methods of attaching the blocks. Doubles and triples feature M-Lock to hold the swivel in front/side position, or to let it spin freely. The triples compact cam arm supports high load purchases of 5:1 or 6:1. The line shedding cheek block features a small mounting footprint and drainholes.