The Serrated/Helix design creates air turbulence in the intake manifold to increase air pressure in the combustion chamber resulting in increased horsepower, torque and improved throttle response. The Serrated/Helix combination design also reduces intake whistle that occurs with other helix only designs. (US PAT 07055513). Made from 6061-T6 Billet Aluminum aFe Silver Bullet Throttle Body Spacers are precision machined for lightweight, high strength and perfect fit. These spacers come with gaskets and use all factory mounting locations for a hassle-free installation.