We’ve all heard stories of athletes sustaining injuries, shaking off the blow and continuing to play on. But is that really safe? Reebok’s Checklight is here to let you know. This head-impact sensor measures the severity of an impact to make it clear whether an athlete is really safe to play on or not.

The Checklight is made of two parts: a sensor developed by mc10 and a skull cap made by Reebok. The flexible sensor fits inside the skull cap and is visible through transparent pieces of the cap. When a player is hit, falls or experiences impact of any kind, a light on the sensor either shines green, yellow or red, alerting both coaches and athletes of the severity of the impact. And while red doesn’t necessarily mean an athlete has a concussion, it definitely does let you know that you’ve been hit fairly hard and should be assessed.

Checklight is available on Reebok’s website for $150, and comes with the sensor, skull cap and charger. It fits perfectly under a helmet, being almost undetectable, and does not add anything bulky or heavy to an athlete’s equipment. Techies at this year’s CES even tested it out when someone volunteered to be punched in the head. Don’t worry, he was wearing protective gear, but the trial proved that Checklight did indeed gauge impact accurately.

In sports like hockey and football, where players often sustain high-impact and serious injuries on a daily basis, Checklight could be seriously beneficial to understanding and assessing their safety during practice or a game, making it players’ (and parents’) new best friend on the field.

What do you think about Reebok’s gadget? Should athletes wear these to help keep themselves safe? Share your opinion with us in the comments below.

(h/t Engadget and Boston Trauma)