The KBO rope lashing, which comes supplied with the block, makes fitting easier and quicker than standard shackles and will never sieze due to load or rust over the years. The cheeks are made from aluminium alloy and the block features a two stage bearare made from Plastic & fibre and the central roller bearings are Peek. The Karver KBO6TJ Triple lashing block with jammer can be combined with the KBO6T for a lightweight, stand-alone 6:1 purchase system.