Prepare your semi to be Ready for the Road Ahead , with the Bendix SR-5 Spring Brake Valve Kit that regulates the transfer of compressed air through the brake system. To provide optimal air pressure levels for the air brakes, this replacement valve controls the pressure level throughout a section of the system. Fashioned with a rugged metal design to tolerate extreme pressures and harsh conditions. FleetPride is your First Click in Heavy Duty .