Yankee Hill Machine Co, Diamond Series Forearm, 9.290", Midlength, Fits AR-15, BlackThese unique forearms feature diamond shaped heat vents, an extended top rail for gap free installation, T marked rails to mark accessory locations, they accept their end caps, and utilize their 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. Features : Black finish