Soft faux leather, the shrinkage looks like elephant skin. I've used it about twice, but the capacity is too small for me, as I carry a lot of things. It has a lot of pockets, which is very convenient, but if you fill the pockets, you won't be able to fit anything in the main compartment. There is no gusset. It can also be worn diagonally with an adjuster. I don't think it's suitable for people who carry a lot of things. Approximately 26cm square. I hope you will consider it. Thank you. Orion