This 20mm Double Dynamic Block with Becket and Hook is not only lightweight and strong, but also offers low friction and fast rolling speeds. Its dynamic range is perfect for applications that require constant sheave movement such as sailing, windsurfing, and kitesurfing. The becket eases tying off, while the heavy-duty hook allows for quick attachment or release. With our patented bearing system and unique Ultra-Strap, this block is superior in load-carrying ability, longevity, and rope-friendliness.