Blower Relief Valve Vacuum Capabilities Pressure Preset Limit 249 in wc Outside Diameter 5.7 in Inlet Size 2 1/2 in Inlet Type NPT Compatible Manufacturer Part Number 2EPR9 2EPT1 Compatible Grainger Part Number 2EPR9 2EPT1 Maximum Operating Pressure 15 psi Minimum Operating Pressure 1 psi Overall Length 7.81 in