Single With P-Clip – 20mm Single Dynamic Block – Our Dynamic range is generally the best choice for applications that require constant sheave movement. Bearings – Dynamic Blocks feature our patented bearing system which uses twin rows of stainless-steel ball bearings running on a stainless-steel rail. This provides a superior load-carrying ability and longevity when compared to other bearing systems which run on a plastic rail. Ultra-Strap – Our patented Ultra-Strap is used in our 20, 30 & 40mm Dynamic blocks. The Ultra-Strap is unique when compared to other designs because of its coining process. This process strengths the strap, making it more reliable and hard-wearing as well as making it much more rope friendly than other designs. The Ultra-Strap was the first marine industry block designed to work specifically with a rope attachment. Becket – Our 20 & 30mm blocks offer a large central rivet which not only reduces the overall weight but also offers a rope friendly attachment, perfect as a tie-off point when being used in a cascade system.