Proper hydration is essential to athletic performance and everyday health, but so far, there isn’t a fitness band that can monitor it.

That changed on Monday, when researchers at North Carolina State University unveiled a low-cost hydration tracker in the form of a wireless sensor, according to a university press release

The sensor works in real-time by monitoring the electrical properties of the skin. This allows it to track hydration because the skin’s electrical properties change based on a person’s hydration.

“It’s difficult to measure a person’s hydration quantitatively, which is relevant for everyone from military personnel to athletes to firefighters, who are at risk of health problems related to heat stress when training or in the field,” said John Muth, a professor of electrical and computer engineering at NC State and co-corresponding author of a paper describing the work.

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So far, researchers have incorporated the tracker into a wristwatch and an adhesive chest patch. Both systems wirelessly send data to a program that’s compatible with laptops, tablets and smartphones with Bluetooth.  

The research, published in the journal Advanced Healthcare Materials, was done on artificial skins with varying levels of hydration and showed that humidity does not affect the sensor’s readings. Therefore, it can be utilized in any environment—from your sweat-soaked neighborhood boxing gym to a crisp day in the great outdoors.

And while this may sound like a device that’ll make your bank account cry, it’ll likely be in the same price range as most of the trackers on the market: “The commercially available monitor we tested our system against costs more than $8,000,” said Shanshan Yao, a Ph.D. student at NC State and lead author of the paper. “Our sensor costs about one dollar, and the overall manufacturing cost of the wearable systems we developed would be no more than a common wearable device, such as a Fitbit.”

Until it makes its debut, though, you’ll just have to keep on your hydration levels the old-fashioned way.