aFe POWER Silver Bullet Throttle Body Spacer is a patented design that increases performance and throttle response. It's unique serrated/helix design eliminates the whistle sound that often occurs when a helix only design is used. Made in the USA from domestic suppliers, this billet aluminum spacer is CNC machined for precise fitment and has a beautiful finish. All necessary hardware and gaskets are provided for an easy and quick installation.