Experience exceptional sailing performance with Lewmar Synchro blocks. With a 50mm sheave diameter and a robust 990 lb. working load limit, these blocks accommodate 1/4" - 3/8" lines. The high-density free-spin bearing boosts efficiency by reducing axle diameter, offering smoother operation and up to 40% less friction. Effortlessly switch between swiveling and fixed setups, and benefit from seamless compatibility with Lewmar travelers thanks to the precision-engineered shackle post. Perfect for halyard tuning, mainsheet systems, mast foot and head blocks, and boom vangs, Lewmar Synchro blocks are designed for superior performance and durability on the water.Lewmar, the world's premier leisure marine equipment supplier, designs, manufactures and distributes winches, hardware, hatches, port lights, glass & glazing, steering systems, bow thrusters, anchoring, and windlass products. They are a proud member of the Lippert family, a leading global manufacturer and supplier of highly engineered products and solutions, dedicated to shaping, growing, and bettering the RV, marine, automotive, commercial vehicle, and building products industries. Lippert's commitment to their customers is always moving forward, always making their experience better.Upgrade with Lewmar Synchro blocks for unparalleled speed and efficiency. Featuring optimized geometry, free-spin bearings, and a self-aligning head, they reduce friction by up to 40%. Enjoy smoother sail handling, less rope wear, and versatile shackle options for lasting performance.