Serrated/Helix Design: The serrated/helix design creates air turbulence in the intake manifold. This turbulence increases the air pressure in the combustion chamber, resulting in increased performance and improved throttle response. The serrated/helix combination design also reduces intake whistle that occurs with helix-only designs (US PAT 07055513). 6061-T6 Billet Aluminum Construction: This Silver Bullet throttle body spacer is precision machined from 6061-T6 billet aluminum for lightweight, high strength, and perfect fit and finish. It features a black anodized finish. Installation Is A Snap: This Silver Bullet throttle body spacer uses all factory mounting locations, making for a hassle-free installation. A supplied gasket provides a perfect seal. Note: This item will work with aFe POWER intakes P/N: 56-70006R & 56-70006D