I chose it due to good reviews. With a price of €55, I definitely have my reservations regarding its durability over time and heavy use *I will come back to this. Polyester casing, average zipper but with straps with iron fastening, low profile black color, the straps are removable and you can carry it like a suitcase. Internally lined with dark gray material helps in finding clothes, I would prefer a slightly lighter color. Volume adjustment, with a peripheral zipper it compresses and so you can use it as a daypack wherever you go. With dimensions 49.5X19X34.3 it is exactly within TSA specifications, you can take it as cabin luggage. Matein offers this particular backpack in two versions, without space for a laptop (1159) and with space for a laptop (6039). I chose the one without (1159) which is lighter and less bulky, you can put the laptop in the spacious external pocket with a sleeve. Empty, the backpack weighs 700 grams, I don't think there is a lighter 40-liter backpack on the market. For a summer destination where you don't need many clothes, you can comfortably pack for a week, the main compartment is very spacious and with good folding can hold a lot of clothes. In winter, the margins narrow, with proper packing and wearing bulky clothes on the plane you can fit clothes for 5 days inside. With one pair of pants, one pair of shorts, 6 t-shirts, 2 long-sleeve fleeces, one internal jacket lining, underwear, socks, a toiletry bag with soaps, etc., the backpack was packed full and weighed close to 6 kilos. At €50-55 it is a VFM backpack, super light, ergonomic, sits very well on the back and is compatible with TSA specifications.