Originally Posted by LapLap

2. The Zuca pro is a frame with wheels with a detachable part made of the fabric and zippers. It's easy to wash and it is this insert that makes the Zuca frame into the Zuca case. The frame is strong enough to be a seat and there are accessories to allow you to make the seat more comfortable and less cold. Our Zuca pro came with an additional travel cover padded at the top which serves a similar purpose.

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3. Can't help you with that question, the Zuca with four wheels is now called the Zuca Sport and is no good for air travel, its main market is ice skaters. The extra wheels are supposed to be good for getting the thing up and down stairs but make it inappropriate as cabin luggage.