The 2171A4917Z is a directional control valve from the 21 Series, vacuum, solenoid pilot-controlled, 2-way 2-pos, spring return, NPT threads, with a 1/2" port, 3/8" body, normally closed, 110-120 V AC, 50/60 Hz manufactured by ROSS CONTROLS. This valve is designed to provide precise control over the flow of air or gas in various applications. With its durable construction and reliable performance, it ensures efficient and safe operation. Trust the 2171A4917Z to enhance the functionality and reliability of your system.