The YHM Diamond Series forearms feature diamond shaped heat vents, an extended top rail for gap-free installation, "T" marked rails to mark accessory locations, accept YHM end caps, and utilize YHM anti-rotation screws for secure installation. The forearms and barrel nuts are made of 6061-T6 aluminum and hardcoated to military specifications. The jam nut and anti-rotation screws are steel and plated a matte black finish to match. The assembly includes: one jam nut, one barrel nut, two anti-rotation screws, and one forearm tube. The overall length is 12.58" and the weight is 15.2 oz.