I'm selling this because I don't need it anymore. I haven't used it at all! However, it is a used item. Please buy it if you're interested. The Yamaha Silent Brass SB7X is a soundproofing accessory that suppresses the sound of your instrument while still providing clear sound quality. - Brand: Yamaha - Model: Silent Brass SB7X - Accessory: Personal Module STX-2 - Function: Soundproofing - Condition: Unused Thank you for looking.