Nuova Simonelli Articulating Steam Wand Nut Kit (01000101.AB)
This kits comes with both the nut for the standard version as well as the new, taller, Aurelia II version. Simonelli #01000101.B (old) and 01000101.AB.
The PTFE lower o-ring that comes with these can be extremely challenging to remove and replace as the PTFE has very little elasticity. We recommend removing the tip, then the rubber heat guard, then the nut and reassembling in reverse.