Purchased on Amazon in July 2025. I'm selling it because I don't use it much. It's almost unused, but there are some scratches from moving around in the included case. These were present since the time of purchase. The retail price was 6789 yen. The following is quoted from the Amazon description: Daconovo French Horn Mouthpiece Pressure Relief Valve Breath Trainer Mouthpiece Pressure Relief Device to Correct Excessive Pressure on French Horns This is an excellent tool that helps monitor pressure usage, regulate breathing, correct incorrect playing methods, and play correctly. Precisely CNC precision engraved and carefully designed, making playing easier. You can adjust the pressure according to your skill level, allowing for easier playing and more accurate and better sound. Made of high-quality brass material with gold/silver plating on the surface, it is very durable and has a smooth and beautiful appearance. The nozzle pressure relief valve is suitable for French horns and is easy to install and use.