La Marzocco 1/4" Brass Anti-Vacuum Valve
1/4" Male BSP. Used in the GS3, Linea Mini, Linea PB and Strada models only. Not the same as the (1/8") one used on the steam valve of the GB5/FB80 or (old version 1/4") Linea Classic/FB70. This can be used to replace any 1/4" anti-vacuum valve.
In the Strada model it is located in the right, rear portion of the machine, by the back of the boiler.
La Marzocco part number B.2.029