SARD R2D2 (RACING BLOW OFF TWIN DRIVE TYPE 2) An aluminum die cast part ensures a super lightweight & compact body. The air capacity of the air chamber increases by having air jackets all around the cylinder valve. A large opening nozzle improves air discharge efficiency, and facilitate the tuning of the intoxicating & addictive blow-off sound. R2D2's air sealing reliability is tremendously improved by integrating the valve & the shaft design. This design also make the R2D2 BOV more compact & lightweight which also equates to a more affordable price. Designed for street cars to track cars.