Vacuum Relief Valves, Vacuum Flow ValvesRelief Valves for Regenerative Vacuum Pumps Model No.: VRV-2-EA Part No. Use with Vacuum Pump Model Number Overall Height in. (mm) Diameter in. (mm) Thread Size VRV-2-EA VB3HF, VB7HV,VB8HF, VB9HV 3.50 – 4.38 (88.9 – 111.3) 3.00 (76.2) 2″ NPT Male