This is just the mute part of a Yamaha Silent Brass. I haven't used it in a while, so I'm not sure if it works, but it attached to the bell without any problems. The physical cover is in place, so the sound is reduced. I think it can be used for practicing at home. The connecting device (I think it was about the size of a small tablet) that came with the set is missing. I haven't checked it by connecting it, so I would like to sell it to someone who understands this.