50mm Synchro Block - SingleLewmar&';s Synchro Blocks are engineered for speed, efficiency, and superior handling. Using a combination of scientifically optimized block geometry, a Free-Spin bearing, and a self-aligning head to reduce friction and increase efficiency by up to 40%, over budget blocks on mainsheet systems. Each component is perfectly synchronized with the movement of the rope, providing you with an easier, smoother transfer of power from deck to sail and less wear on your rope.Features: Stainless steel strap for improved strength and longer service life Stiff glass fiber reinforced cheeks to prevent lines from wedging Innovative design with "tool-free" sliding swivel locking mechanism Technical Specifications: Working Load Limit - 990lb Weight - 2.36oz Maximum Line Size - .39" (10mm) *Sold as an Individual