This Allen 16mm Block features a Black Acetal Sheave and a 16mm Single Plain Bearing Block With Acetal Sheave. It is designed to be lightweight and cost-effective, making it perfect for low loaded systems like control line bungee take-ups or rope guides. The acetal sheave utilizes a plain bearing that has a long lifespan and requires minimal maintenance. Plus, the block's body is made of stainless steel, providing a lightweight and sturdy frame.