Purchased one year ago. It's an external music sheet bag that can be attached to an instrument case. I was using it attached to a tenor saxophone's Shiny Case. Images 6-8 are from the purchase site. *I disposed of the 135cm strap that came with the set because I didn't use it. A4 size sheet music fits easily! The part that touches your back is made of mesh cushion material, so it's soft and less likely to hurt your back. I'm selling it because I got a new instrument case and no longer use it. Please understand that this item has been stored at home, and I appreciate your purchase◎