Serrated/Helix Design: The serrated/helix design (US PAT 07055513) creates turbulence in the intake manifold and increases air pressure in the combustion chamber for better performance. This unique entry design also reduces intake whistle that commonly occurs with other helix-only styles. Longer Intake Tract: The addition of a Silver Bullet throttle body spacer lengthens the intake tract, which increases air intake speed, resulting in improved throttle response and overall performance. 6061-T6 Billet Aluminum Construction: All Silver Bullet throttle body spacers are precision machined from 6061-T6 billet aluminum for lightweight, high strength, and a black anodized finish. Premium Hardware: This Silver Bullet throttle body spacer includes quality, machined screws, allowing for a secure, factory-like, non-damaging install to your factory intake manifold. Fitment Note: This throttle body spacer will fit aFe Power intakes P/N: 51-81012-B, 54-81012-B, 51-81012-C, 54-81012-C, 54-13053D and 54-13053R.