Designed to deliver more horsepower and torque, aFe Silver Bullet throttle body spacers make an excellent addition to your vehicle. They're precision-machined from T-6061 billet aluminum to exacting specifications to provide optimal performance. The combination serrated/helix design creates turbulence so that the air/fuel charge is thoroughly mixed for a complete burn. Their specially-designed serrated edge will reduce the whistling sound normally associated with throttle body spacers. The aFe Silver Bullet throttle body spacers increase the volume between the throttle and cylinder, improving volumetric efficiency.