Thank you for viewing. This is a sterling silver mouthpiece pipe for an E.S. Shires tenor/tenor bass trombone. The model number is "3SS," and compared to 1 or 2, the sound is more open (wide), but compared to a brass mouthpiece pipe, it is tighter and the sound density is significantly improved. Once you try it, you may not be able to go back to brass (sweat). This product is often sold out in musical instrument stores and is difficult to obtain, so please consider it. m(._.)m