Update your semi truck with increased safety standards, with the Bendix ST-4™ 160 psi Safety Valve that ensures you're Ready for the Road Ahead™. By utilizing a sophisticated design, this replacement component is able to relieve excess pressure from a vehicle once it surpasses a set level. Constructed with an advanced system to prevent the air compressor from damaging the brake system. FleetPride is your First Click in Heavy Duty®.