This is an Alexander horn mouthpiece from the "Exclusive Line" designed by Francis Orval. The model number is Cup "5 1/2S" + Rim "5 1/2W". ・The Alexander horn mouthpiece "Exclusive Line" was launched over a decade ago with a lineup of 9 cup inner diameters (gold-plated, V-cup and U-cup) and 27 rims (gold-plated and silver-plated). ・I apologize, but I have forgotten the specific specifications of the "5 1/2S" mouthpiece. However, the cup inner diameter is 17.75mm, U-cup, and gold-plated. By the way, the rim is compatible with the rim threads of TAD horn mouthpieces, so it can be used by changing to a TAD rim. ・There are scratches on the outer surface of the cup and shank, and the gold plating is dull, but the gold plating on the rim and the inner surface of the cup is believed to be in good condition. ・This is a rare mouthpiece with infrequent listings. If you are looking for one or are interested, I will sell it at this price.