Save space with the the HK-S4-V228 that features a pump/tank assembly that takes up just over half a cubic foot of space. This system reaches a full 145psi for extra loudness when you need it. The tank is 2 gallons. The S4 black shocker horns feature a tough ABS composition that saves weight and are virtually indestructible. The trumpets can be installed separately for ultimate install versatility. People will react to the Shocker 4 horns, you can count on it!