What does expandable mean on these suitcases?

A zippered expansion section lets each case gain extra packing depth. It is useful for souvenirs or bulky items, but the bag becomes thicker and may not fit tight overhead bins when open.

Is this set good for a family of four?

It depends on the piece count and sizes in the set. Check that the largest case covers checked baggage and the smaller ones work as carry-ons for each traveler.

Are the bags hard-shell or softside?

The set is described as flexible and expandable, which points to softside construction. Softside bags flex and have exterior pockets but protect fragile items less than hard shells.

Can the cases nest for storage?

Smaller cases in a matching set usually fit inside the largest one. Confirm the sizes, since nesting works best when each case is clearly smaller than the next.

Do the wheels and handles suit air travel?

Most sets in this category use spinner wheels and telescoping handles. Check that the largest case has four wheels, since a loaded checked bag is hard to drag on two.