Ideal for low loaded systems, such as control line bungee take-ups or rope guides. Plain Bearing – The acetal sheave spins around the central axle. This type of bearing has a long lifespan and is very low maintenance. Lightweight Body - The body of this block is formed in stainless steel for a lightweight yet robust frame. Through Deck - This block is designed to guide rope or bungee through a surface. It offers less friction than a deck bush, but cannot withstand high loads.