La Pavoni Lever Professional Pressure Gauge Nut (Chrome) OEM Part No.2120042451

Does Not Fit Post Millenium Models but measure first as some older Europiccola models did use the M12 size.

If you decide you want to install a Pressure Gauge on your post Millennium Europiccola the best way is to purchase an adapter from HERE

Used as standard on the La Pavoni Stradivari Professional SPL and SPH. The La Pavoni Professional PN, PL and PLH the La PavoniRomantica GRL and Stradivari Gran Romantica SGR.
Also use with the Gaggia Factory G106