This foldable carry-on bag expands into a full-size suitcase

Everybody's an expert when it comes to packing before a vacation. It's great that you squeezed all that stuff into a carry-on. Now, what happens when you find that must-have pair of shoes or holiday gift? Your options are paying to ship the items or getting an extra bag, and neither of those is ideal.

Turns out there's a travel bag that solves that problem so easily, it's kind of embarrassing that no one's done it before. At least, not as well as the Rollux 2-in-1 Expandable Suitcase:

Rollux Suitcase

The simple folding design means you can convert this carry-on bag into a full-size suitcase, more than doubling its carrying capacity in seconds. It's intuitive enough for even the busiest traveler to collapse or expand without instructions, and that extra space can be a godsend for long trips. When you get to your destination, just fold it up and save yourself extra space in the hotel closet. While in its carry-on mode, it can even be worn as a backpack if you're hoofing it for awhile.

This isn't a one-trick pony, either. There's plenty of thought put into the polypropylene material, which has durability and flexibility to spare. Need to pack a few extra shirts in? Feel free to stretch it out. And it's water-resistant, too - a big plus for long hikes in unfamiliar territory.

The modular design doesn't stop with the interior. The wheels are sturdy but can be easily removed if you need that extra inch or two of space in the overhead compartment. Need a workspace while you're waiting at the airport or lobby? There's a flat surface that folds out on the top, turning your luggage into a makeshift desk. And as smart as the design is, there's an additional perk for smartphones: A USB charging port that can be hooked up to your choice of portable batteries, making for easy charging on the go.

It's really a gamechanger for any traveler, and it comes in a variety of color options - all on sale for 15% off at $295. Get it in blue, orange, or turquoise.