The Linx IAS by BlackBox Biometrics monitors and rates any concussive or sub-concussive head impacts an athlete suffers over the course of a season, stores that information, and makes it available via a slick smartphone app. Significantly, over time the accumulated data can be used to gauge the danger of chronic traumatic encephalopathy (CTE), thought to be the cause of memory loss in professional athletes. The data may also help scientists learn more about the dangers moving forward.
The device itself is small enough to fit inside a headband or skull cap, and was developed in conjunction with the U.S. military. It records the rotation and force of each blow to the head and even lets the user know when medical attention is necessary. At under $200, it's a great option for youth athletes, their parents, or even whole teams.