Thank you for viewing.ᐟ‪‪‪ This is a frame to prevent deformation of square backpacks. Designed exclusively for the TSOG square backpack, "The One," which I personally love. It can also be adapted to other square backpacks. Square backpacks are easy to use and have excellent design, but they tend to lose their shape. Why not go out with your backpack maintaining its beautiful shape from when it was new? It also solves the hassle of stuffing it with things for maintenance! We especially recommend this to those who have just bought a new square backpack, before it loses its shape.‪ꔛ‬ - Product Details - Material: Stainless steel, no burrs Weight: Varies slightly, around 30g How to use: Instructions are included. Basically, you just place the frame along the inside of the square backpack and set it. If you would like fixing tape, please request it at the time of your order .ˬ.)" *The square backpack "The One" is 43cm tall and 17L. Since the product itself is flexible, it may be adaptable to other square backpacks, but please consider this at your own risk. ~Personal Impression~ The more I use the TSOG "The One," the more I appreciate this frame. It keeps the shape looking cool, and makes the storage of the square backpack much easier to use.