Bag size (L) 21.7 x (W) 10.2 x (H) 11 inch fits personal item, which can be placed under the seat, and no need to pay carry-on. Fold up when you not use, does not take much space in your luggage, unfolded as an extra bag for souvenirs or clothes when traveling leaves room for valuables in your suitcase, or used as a carry-on with decent size to fit under an airline seat or in the overhead bin in case you are overweight for a checked bag.