Apco Combination Air Valve: The combination air valve can be used by pipline contractors to purge air from a pipeline after a new pipeline is installed. It allows large volumes of air to escape the water line when filling a pipeline with water. It can also be used when a pump is used to pump water. It was purchased new, never installed. The retail price of the valve is $300., selling for $150., no haggle price. In Escondido, call (760)746-7209