From neck hammocks that hang from doors to inflatable pillows, you’ll find no shortage of neck-decompression tools out there. Some are better—and safer—than others. But what exactly does it mean to “decompress” your neck, and when is it necessary? R. Alexandra Duma, DC, a sports chiropractor at New York City recovery and wellness studio FICS, explains decompression is useful when the nerves in your neck get pinched or irritated.

“Because the neck tends to be a bit more fragile structure and not quite as strong as let’s say the lumbar spine, we can be at risk for some irritation, disc bulging if there’s just too much exercise, pressure, or trauma in there,” says Dr. Duma, who is also a Team USA sports chiropractor. A compressed neck can lead to pain that can manifest down the arm, into the leg, and-or into the shoulder blade.  “A way of helping this and relieving some of the pain is trying to decompress that area, giving you a bit more space in there so that the nerve can travel a bit more freely.”

But before you chalk up your neck pain to compressed nerves, Dr. Duma says you want to make sure that’s actually the issue. The best way to do this is to visit someone like a physical therapist or chiropractor, she says. But to test it at home, she says to roll up a towel and place it under your occipital bone at the base of your skull. Grabbing the ends of the towel, gently pull it up.

“If this definitely eases the pain right away or relieves some of the numbness right away that’s going down the arm, that’s an indication that, ‘Okay, this technique can work,'” she says. If that’s not the case and this causes more pain, the root of the issue lies elsewhere and decompression can exacerbate both the issue and the pain.

When you get decompressed by a pro, the length and intensity of the session is carefully decided, explains Matt Cooper, DC, founder and CEO of USA Sports Therapy.

“We use decompression in our office, but it’s carefully measured based upon the severity of the condition, any changes in the cervical curvature, and the amount of spasms in the neck,” says Dr. Cooper. “We also progress the length of the decompression therapy session and the amount of pressure applied, over time to enhance effectiveness.”

When it comes to at-home devices, he’s not a fan of any that hang off of a door due to the inability to control your head.

“Additionally, depending on where the chair is set up in relation to the door and or traction device, these devices can cause instability, and place your neck in an awkward position,” says Dr. Cooper. “This may exacerbate your symptoms, making your condition worse.”

He instead recommends using the Saunders Cervical Traction ($348) and the ComforTrac ($225). They’re what he prescribes to outpatients for home use, after properly diagnosing each patient and explaining how to correctly use them for their unique condition. Be sure to consult your physician for guidance on how to use these tools prior to use.

If you’re not looking to shell out that much, Dr. Duma says you can use that rolled towel again—30 seconds on, 30 seconds off—for three to five rounds. If you’re opting for an inflatable pillow, be extremely careful and don’t overdo it. “There have been some studies that actually, I think the most recent ones were in 2015, where they’re looking at these inflatable neck traction devices and sometimes they can irritate and move in a strange way, the smaller neck muscles from the excessive pulling of the muscles,” she says. Pillows should be used for no more than two minutes, giving your body a few minutes rest in between for three to five increments.

Whatever tool you use, don’t overdo it. That means you shouldn’t spend hours with it on and definitely don’t fall asleep in it. And if the root cause of the compression is something you can control, try adjusting that instead of relying too heavily on decompression tools.

“Is it a matter of posture? Is it that you’ve been at a computer for an excessive time in that position or your neck starts to hurt?” she asks. “We will use the decompression device, which is great, but then if you’re still not addressing the other factors that caused this type of pain, you’re doing yourself a disservice.”