Ligament tears occur about 60 milliseconds, but a startup claims to have created a knee airbag that inflates in just 30 milliseconds, enough to prevent ACL and MCL injuries.

Hippos, a startup founded by Kylin Shaw and Bhavy Metakar, recently raised a $642,000 pre-seed round from investors Possible Ventures and Silicon Roundabout Ventures for their revolutionary “knee sleeve,” a sort of high-tech airbag for the knee that uses sensors to rapidly detect incoming stress and deploy tiny air canisters that fill up small airbags around the knee, thus preventing critical injuries. It only takes 30 milliseconds for the knee airbag to inflate, considerably faster than the 60 milliseconds that ACL injuries typically occur in. If the device works as presented by the company, it could save athletes thousands of dollars in medical expenses and much more in inactivity.

“I, myself, have loved basketball since I was six years old, and for the next decade, it became my entire life,” Kylin Shaw told TechCrunch. “I dedicated myself to intensive training. … But at 17, just as I was preparing for a professional basketball career and NCAA trials, I heard a sickening pop from my knee while landing from a dunk.”

The knee injury ended his aspirations of a career in basketball, but it also allowed him to focus his efforts on finding a way to prevent similar injuries. Interestingly, most of the solutions available on the market today focus more on rehabilitation and post-injury support, and the few devices that do exist in the space are not very efficient.

So far Hippos has performed trials with several U.K. football clubs and a number of athletes, such as world skiing champion Alex Schlopy, and the results are very promising. The company has already secured six figures in pre-orders, which it plans to re-invest in improving the knee airbag. A full launch is expected in about three months.

Although the concept of an AI-powered knee airbag is intriguing for investors and athletes alike, the monetization model presented by Shaw and his cofounder has attracted some criticism online. Apparently, the device will sell for about $129, but users will also have to pay $29 to $99 per month as part of a subscription plan covering features like AI insights and extra air canisters.