Unfortunately, the external dimensions not vote - really are 55 x 40 x 23 cm (!). The 23cm depth arising from the rollers and the plastic floor. It can thus be saved by ideal pack anything at this depth. The backpack is therefore not to be used as airplane carry-on luggage. It is quite understandable that there are already reviews, which provide for this alone a bad overall - after all, is alone in the name of the article of "flugzugelassem hand luggage" is mentioned.
Impractical I find that the coverage of the strap is folded down, as with most trolley backpacks and so obscures the roles. A change between backpack and trolley or vice versa is possible only with effort. Especially with long stairs it would be useful if you quickly push together the telescopic handle and could directly shoulder the strap. Instead, you must first open a Zip that cover the strap Fold down the backpack tilt, turning the cover and secure via push button and Velcro on the bottom of the backpack. This is too cumbersome - this bag is for people who need to travel a backpack and on another trip a trolley. Who can find a quick change between the two modes is important should look for alternatives.
