The standard Suzuki mouthpiece is the MP-121, Tommaso. There are several different Suzuki A-32 models, all good. The MP-121 fits all of them. It is readily available on eBay, shipped for free from Japan. The cheapest one I see at the moment is linked below, though that’s delivered to the U.S. If you are not in the U.S., search in your regional eBay for “Suzuki MP-121” or do a more general search. But be careful not to pay more than $10-15 U.S. including shipping.