This valve can be used as a brake shut - off. When energized, the valve will block pressure from reaching downstream. The valve does not prevent fluid from returning to the master cylinder. This eliminates the possibility of trapping pressure when activating the valve. Requires a 12 Volt, 5 amp (recommended) fused power source through a toggle switch. Warning Not a line lock assembly. Not for street use. Please read instruction sheet available at httpwww.wilwood.compdfds572.pdf before attempting installation