Old but new unused Rudy Muck 13C Cushion Rim Cornet Mouthpiece
Unopened in original black, leatherette purse. The writing on some of the covers is faded, as can be seen in photo.

I don't know very much about these mouthpieces apart what is engraved on them and printed on the purse.

A previous satisfied customer has told me :
"I bought this particular mouthpiece as a backup cornet mouthpiece for both Bb Cornet and Eb Soprano Cornet. I play in brass bands and do session work and had heard about the way the thick rim can aid/slow fatigue in and around the mouth muscles." J.

I asked if it fitted
"It did, a little loose on the soprano, but my particular remodel has a slightly larger/older/worn bore so no surprise there" J.

"Got this for soprano cornet. The shank on the mouthpieces is actually at bit small and you will need to push it in and adjust the cornet tuning slide" SC