The Madbull Airsoft 1" Outer Barrel Extension is 14mm CCW (negative) threaded and made from anodized CNC aluminum. It's counter-clockwise threads allow this extension to fit on a majority of airsoft rifles and extend the outer barrel length by 1". This is extremely useful for rifles that have the inner barrel protruding out of the outer barrel or have a rail system that is longer than the outer barrel making it difficult to mount mock suppressors or flash hiders. Comes with a vibration minimizing rubber o-ring that holds the inner barrel in place to improve overall accuracy.