The NFL has argued it didn't intentionally mislead the players and took steps to protect their health.
More than 30 NFL players have in recent years been diagnosed with chronic traumatic encephalopathy (CTE), a degenerative disease typically caused by multiple hits to the head.
A team of scientists who analyzed the brain tissue of renowned NFL linebacker Seau after his suicide last year at age 43 have concluded that the football player suffered from CTE, likely caused by two decades worth of hits to the head, researchers and his family exclusively told ABC News and ESPN earlier this month.
"A lot of things, towards the end of his life, patterns that we saw and things that worried us, it makes sense now," Gina Seau, his ex-wife, told ABC News and ESPN.
Reebok told ABC News that the CheckLight device is in its final stages of development and it expects to make them available in June, retailing for $100 to $200.