A revolutionary new technique is enabling burn victims to heal quicker, less painfully, and with more normal skin. And it’s all thanks to a gun. The SkinGun sprays stem cells onto wounds and allows patients to grow a new, healthy layer of skin in as little as four days, according to the Daily Mail. More than 60 patients have been treated with this new technique, and RenovaCare, the company behind the gun, is applying for the FDA to allow it for use in routine clinical practice.

Here’s how it works: a small patch of skin, the size of a postage stamp, is removed from the patient so the stem cells can be separated out. Those stem cells are then put into a solution to be sprayed on the wound. In total, the process takes just 90 minutes. And the new skin is virtually indistinguishable from the rest of the body. (Stem cells have even been touted for their abilities to cure erectile dysfunction.)

“The procedure is gentler,” said Thomas Bold, CEO of RenovaCare. “And the skin that regrows looks, feels, and functions like the original skin.”

Normal skin grafting is a painful process that takes large chunks of skin from the body and can take weeks or even months. Plus, there’s the issue of scarring. With the SkinGun, a man who suffered electrical burns on more than a third of his body saw his skin heal in just 20 days after 24 million skin cells were harvested from an area smaller than an iPhone. If the SkinGun makes it to widespread use, it’ll be a real game changer—and we won’t even have to worry about controversy from the source of stem cells.