Experience a sailing upgrade with Lewmar 72mm Single Synchro Block, designed for optimal speed and efficiency. With scientifically shaped geometry and a Free-Spin bearing, these Lewmar mainsheet blocks enhance efficiency by up to 40%. Features include a stainless steel strap for durability, stiff glass fiber cheeks to keep lines in place, and a tool-free swivel lock. Ideal for halyard tuning, mainsheet systems, and more.