The Carlisle Brake & Friction single circuit and parallel circuit relay valves are capable of providing high flow to large displacement brakes to give quick brake reaction times. Modulating output pressures in a range of 600-3,500 psi (41 to 241 bar). The relay can be piloted by a pedal valve, remote E/H proportional valve or an integrated E/H proportional valve. Optional differential pressure switch monitors for brake failure.