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: All Silver Bullet throttle body spacers are precision machined from 6061-T6 billet aluminum for lightweight, high strength, and perfect fit and 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.