Update your semi truck with a safe way to vent engine gases, with the Dorman 904-7903 Crankcase Breather Element that ensures you're Ready for the Road Ahead™. Due to its straightforward design, this replacement device is able to filter harmful gases produced in an engine before releasing them into the atmosphere. Constructed with premium materials to be resistant to both heat and oil. FleetPride is your First Click in Heavy Duty®.