Backpack strap fixing bands?! Comes in a set of 4. Useful when you have excess backpack shoulder strap. (Note) Photos ③ and ④ show usage examples. Usage examples are included. Photos ③ and ④. The inner diameter of the rubber band is not adjustable, so in the case of a covert case, the strap might be thin? Therefore, the inner diameter is a bit large, and it's attached at the top like in the photo, and it looks like this.