O-Ring For 3-Way Solenoid Valve, SOLD in Set of TWO at $1.32 each and 2 for $2.64
Fits:
Parker
Lucifer
and more, including La Marzocco Linea line steam valve shaft
NOTE: New valves include the O-Rings. If you are just replacing the O-Rings on your valve, TWO are needed for each valve, and purchasing 1 of this item includes 2 O-Rings.