Ever wonder why you’re always dealing with back, neck, or shoulder pain? Your posture is probably at least partially to blame. But it’s hard to remember to sit up straight when mom isn’t around and your seat seems designed to make you slump. (Why does that always feel like the comfiest way to sit?)

Luckily there’s an easy way to improve your posture: the BetterBack. The packaging is unassuming: It looks like a laptop case with cloth exterior and zipper. Unzip it and find a magical contraption inside, though admittedly one that looks like a huge rubber band.

When you’re sitting down, place the back pad against your lower back and the knee pads (you guessed it) around your knees. Then adjust the straps to your ideal posture. It’s basically a seat belt for sitting up straight, and it’s crazy how quickly we saw a difference. A few minutes into wearing the BetterBack, we felt so relaxed (everything was where it was supposed to be, not squished together). The craziest thing? After wearing it for a few hours, we noticed our posture got better even when we weren’t strapped in. And perhaps the best news of all: Greatist readers can get 15 percent off BetterBack by using the code GREATIST15 at checkout.