I used it only once, but it was too small for my luggage, so I'm selling it. It's in overall good condition. The outer material uses a sturdy and tough ballistic polyester fabric. It's also water-repellent, so you don't have to worry about sudden rain or getting wet. The storage space is large enough to hold A4 size items, as well as B4 size items. The opening can be closed with a water-stop zipper, so you don't have to worry about the contents being visible from the outside. Inside, there's a zipper pocket convenient for storing valuables, as well as a cushioned pocket that can safely store a laptop or tablet (up to 15 inches). The rubber part for attaching it to a suitcase on the back has been cut off because I didn't need it. There's no problem with using it, but please refrain from purchasing if you are concerned. Top width: approx. 29.0cm Bottom width: approx. 29.5cm Opening (cushion pocket): approx. 27.0cm Height: approx. 42.5cm Depth: approx. 14.5cm Handle (grip): approx. 65.0cm