KEY FEATURES:
1. CNC Lightweight Alumninum with matte black anodize (seamlessly integrates with Madbull black outer barrels).
2. CCW threaded on both ends.
3. Hides extra inner barrel slack.
4. Adds space for quick detach or other barrel accessories.
More info: http://madbull.com/catalog/index.php?main_page=product_info&cPath=5&products_id=418