Is the 20-inch bag carry-on size?

Yes. The 20-inch case is sized for most major US airline carry-on limits. Check your airline's exact dimensions before packing, since limits vary slightly.

Does it have a TSA lock?

Yes, the set includes a built-in TSA-approved lock, so security can open it without breaking the zipper. You set your own combination.

What is the shell made of?

The shells are polycarbonate, a flexible plastic that flexes on impact rather than cracking like ABS. It can still scratch over time.

Do the bags nest inside each other?

Yes. The 20-inch fits inside the 24-inch, which fits inside the 28-inch, so the set stores compactly between trips.

Are the wheels spinner or inline?

The set uses four-wheel spinners, so each case rolls upright and can be pushed alongside you. Budget spinner wheels are the part most likely to wear out first.

Is it worth it over buying bags separately?

A matched set usually costs less than three comparable hardshell cases bought one at a time. If you only need one size, a single better-built bag may last longer.