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.