what are nfl players wearing on their necks

NFL players are wearing a device called the Q-Collar around their necks. The Q-Collar is a high-tech band designed to help protect the brain during sports activities by gently compressing the jugular vein, which increases blood volume in the skull. This increased blood volume creates a cushion that reduces brain movement (or "sloshing") inside the skull during impacts, potentially minimizing the effects of subconcussive forces common in football. The Q-Collar is FDA-cleared and is worn by several NFL players to provide this internal brain protection, though it is not intended to prevent concussions directly but rather to reduce internal brain injury risk from repetitive impacts.