The Reebok MC10 CHECKLIGHT is a sports and activity impact indicator that measures the severity of blows to the head when worn during play. It is positioned as wearable electronics directly on the athlete, not simply on his protective equipment. The skullcap can be used in all helmeted and non-helmeted contact sports and activities. Motion sensors directly coupled to the head provide impact data, while the severity of the impact is displayed as red and yellow lights.