Simply insert these little ear plugs in your ears then decide which mode you want to be in. First; push the button in to open the valve- you’ll hear sound clearly and naturally. Then when loud sounds hit your ears, the Dynamic Sound Valve™ will automatically screen those sounds out protecting your hearing. Second; simply close the valve by pushing in again for total hearing protection. These are small, handy and can go anywhere with you. Perfect for Outdoor and Indoor Activities of All Types; Fitness, Cycling, Hiking, Stadium Events, Tactical, Auto Racing, Shooting, Hunting, Concerts, Musicians, Night Clubs, Industrial, Construction, Motorcycling and more.