Is this bag a backpack or a shoulder bag?

It is convertible. You can wear it as a backpack or carry it by the shoulder strap, depending on how you route the straps.

How much can it hold?

The stated capacity is 36-55L, which covers a few days of clothes plus a laptop and small accessories. Actual usable space depends on how full you pack the soft sides.

Is it really waterproof?

The PU leather surface resists rain and splashes, but seams and zippers are not sealed. Treat it as water-resistant for light weather, not submersible.

Does it fit carry-on size limits?

At the smaller end of its capacity it is close to standard carry-on dimensions, but a fully packed 55L soft bag can exceed some airline limits. Check your airline's size rules before packing it full.

Is PU leather durable enough for frequent travel?

PU leather is lighter and cheaper than real leather but tends to crack and peel over years of heavy use. It holds up for occasional trips better than daily commuting.