BEST BRASS 5X フリューゲル用マウスピースの高価買取価格

The product you mentioned, the **BEST BRASS USED 中古 ベスト ブラス グルーヴシリーズ 5X フリューゲ ルホルン用マウスピース**, appears to be a used French horn mouthpiece from the Japanese brand Best Brass. The "Groove Series" suggests it may have specific design features aimed at improving performance or playability. The "5X" typically indicates the size or model within the series.
If you have questions about specifications, compatibility, or where to purchase it, feel free to ask!