The Rocket Booster Gray Center-Machined Outer 1 pc wheel was purpose built to deliver big style and performance for the finest muscle cars, pro-touring and street machines at very affordable prices. The Rocket Booster is precision-crafted from A356 aluminum and topped off with a vintage style aluminum o-ring center cap. The Booster is also available in Full Chrome as well as Hyper Silver Centers with Machined Outers.