Holiday travel is stressful enough without adding cramped seats and long flights into the mix. Anyone who’s spent hours wedged in an economy seat knows how quickly stiffness sets in. Luckily, there’s a simple product that promises a small but meaningful upgrade to your next flight — and reviewers describe it as being “cheaper than first class.”

This bestselling foot hammock makes your airplane seat a more comfortable place to settle in, elevating your legs and taking pressure off your lower back. Travelers call it a “must-have travel accessory,” saying it provides real comfort and relief on long flights and, in one case, even “saved my legs” on an overseas trip. If you’re traveling soon, then we’ve got even better news: Amazon says that this $20 gadget should arrive before Christmas, making it an easy upgrade before your next flight.

The in-flight foot hammock is easy to set up, pack and use during travel.

It’s an unobtrusive design and a truly smart idea. Just wrap the hammock strap around the tray table in front of you, adjust the strap to your desired length and kick your feet into the sling. You can use the device with your seat tray table open or closed, and the brand says it’s compatible with anyone between the heights of 4 and 7 feet. The sling’s depth, meanwhile, can fit between 9 and 18 inches of shoe space. Also, reviewers say when it’s packed in its cinch bag, it’s nearly flat and can easily fit into a suitcase or backpack.