Allows servicing of the system without disrupting other users or draining air from the tank. Brass body with plated steel ball and Teflon seals ensures a long life. High capacity airflow design reduces pressure drop to tools for improved performance. Great for use as a moisture drain. Use with 1/4 In. I.D. piping or hose. Unit has 1/4 In. NPT male thread on one side and 1/4 In. NPT female thread on the other. Use Teflon tape for airtight connections.