This Radiator Steam Vent by Hoffman is model #1A. It’s a float type vent with a ⅛" NPT angle connection. The maximum operating pressure for this steam vent is 10 psig (0.7 bar). It has an adjustable port for true proportional venting with 6 port settings from slow (1) to fast (6).
EC Part Number: #57824
Manufacturer Number: 401422
Manufacturer: Hoffman