Nuova Simonelli Flat Group Head Gasket
Nuova Simonelli have switched back and forth from this flat style to the conical version numerous times. Either will work and there is no discernible difference in performance, it is a simple matter of personal preference. This version fits all commercial models (except the Aurelia which uses S_418), as well as the Oscar model.
For the home units, such as the Ellimatic or "Elli" use S_1.
The advice on how to remove the old ones was very helpful.