This is a cup mute for tenor-bass trombone. I purchased it in April 2025 and used it for about six months. It's made of nylon and is characterized by its lightness. It's used with the adjustable cup attached. (Please see the BRASS DESIGN website for details.) - Brand: BRASS DESIGN - Model Name: MUTE for Trombone - Color: Black - Included items: Instruction manual, parts bag, cork-like attachment Thank you for looking.