This 20mm Double Dynamic Block comes equipped with a Swivel Hook that provides low friction and allows for fast rolling speeds. It is both lightweight and durable, making it an excellent choice for dinghies, windsurfing, kitesurfing, and other activities that use smaller diameter lines. The patented bearing system, featuring twin rows of stainless-steel ball bearings on a stainless-steel rail, offers superior load-carrying capabilities and longevity compared to other bearing systems that use a plastic rail. The swiveling hook allows for easy attachment and removal, while also being able to align with changing pulling forces. Please note that the swivel cannot be locked. Additionally, the block features a large central rivet that reduces weight and provides a rope-friendly attachment point, perfect for use in a cascade system.