Aluminum Bolt Extension Gen 3 Folder - The Sylvan Arms Aluminum Bolt Extension allows you a lighter alternative than the standard 3.1 oz Bolt Extension that comes with our folding stock adapter. A common reason people may want to switch are if youre encountering cycling issues, most common when running a heavy buffer or 300 blackout. Will not fit Gen 4 Folder Product Details Weight: 1.09 oz. Finish: Flat Black Anodized If you have any questions, feel free to contact us!