Outfit your semi truck to be Ready for the Road Ahead™ with increased safety standards, with the Prima Brake Components ST-4 Style 250 psi Safety Valve. With a sophisticated design, this replacement component is able to relieve excess pressure from a vehicle once it surpasses a set level. Fashioned with an advanced system to prevent the air compressor from damaging the brake system. FleetPride is your First Click in Heavy Duty®.