Rennline?s billet aluminum throttle control knobs are the perfect inexpensive interior upgrade for any Porsche equipped with this feature. Factory throttle control knobs become faded, cracked, and/or unsightly after years of exposure to UV light. Rennline billet knobs are machined from 6061 aluminum and are available in red, silver or black anodized finishes for a durable, long lasting appearance. Simply tap off your old knob, and tap Rennline's?on, installation is literally a snap.