Having had a special mould made by my supplier, I now sell reproduction case grommets to fit the Olivetti Lettera 22 and many other Olivettis (including full-size standards like the Lexicon 80 and D82)  These also fit the Invicta/ Olivetti MP1, where they are used at the back of the machine as baseboard hinges.  Here is a link to the relevant section of my website :  http://thetypewriterman.co.uk/supplies.html   Worldwide postage is not a problem (a set of grommets will easily fit into an envelope).  I take PayPal payments !