Discussion about Rock Members Medium Ultra Lightweight Foldaway Holdall - Black
I guess you are asking because you are interested in taking it with you during a flight. Correct? If yes, then I would say that it is small enough ( D20 x W40 x H55) to satisfy the dimension criteria of most airlines as you can see here
But this also depends on what you put inside it because apart from dimensions there is a weight limit that differs from airline to airline.
Having traveled many times in the past couple of years I think that with 99% probability you will be allowed to carry it with you as long as you don't fill it with anything too heavy as to exceed the weight limits
Would this bag be classified as hand luggage ?