20mm Single Dynamic BlockBall bearingsLength 77mmFor ropes from 2.5 to 6mmBreaking load 650kgWorking load 320kgWeight 86.9gr. 20mm Single Dynamic Block The A2020 is our go - to low friction, fast rolling, small pulley. It's lightweight and strong, making it ideal for dinghies, windsurfing, kitesurfing and anything else that runs smaller diameter lines. 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 strengthens 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. Video link 20MM SINGLE BLOCK A2020 Technical documents can be downloaded here