Pro Design Billet Cool Head with 20cc Domes The Pro Design Billet Cool aluminumCNC cylinder heads with 20cc Domes Billet are perfect for your high performance bike. These state-of-the-art cylinder heads are designed with replaceable combustion chambers for easy tuning and custom order for your application including; altitude, port timing and fuel. Pro Design Billet Cool aluminumCNC cylinder heads provide up to 70 Percent better cooling pluse increased reliability. The CAD assisted designed combustion chambers insure maximum performance for your bike. Compatible with: Yamaha Banshee 350 (All Years)