XP Defender Earplugs offers you one of the most innovative ear plug solutions yet. Simply insert these little ear plugs in your ears then decide which mode you want to be in: First, leave the valve open- youll hear sound clearly and naturally, then when loud sounds hit your ears, the Dynamic Mesh Filtering System will automatically compress those sounds to protect your hearing. Second, simply close the valve for total hearing protection. These are small, handy and can go anywhere with you, so you always have hearing protection when you need it without blocking off all your hearing.