Allen 60mm Dynamic Blocks feature our patented Dynamic bearing technology, which comprises of high quality stainless steel ball bearings running on stainless steel rails provide unsurpassed performance under load. The large central hole for tie-on becket requirements, give this block range a distinctive style and significant weight reduction. Available with different accessories, making the 60mm dynamic range the ideal choice for Keelboats and large Catamarans. They can be used in a variety of applications from jib sheet to mainsheet systems and everything in-between.