Vacuum Pump - Brake,12V Electric Vacuum Pump - Vane Style, Cast AluminumFor vehicles using engine combinations that provide little or no manifold vacuum required for braking. When vacuum drops below 15 in. of vacuum the CVR Electric Vacuum Pump activates and increases the vacuum level to 20 in. of vacuum. Complete self contained unit. Simply connect the positive negative power and the unit will regulate the vacuum level itself. Unit can be mounted in any position. Patent Pending Design Superior To Anything On The Market