This unique product offers superior noise-blocking (NRR of 33dB) performance in a reusable, high-end earplug. Its enhanced contoured shape is easy to insert and the proprietary material offers superior long-wearing comfort, delivering solid performance that you can depend on. The patented Impulse Filter Technology, automatically engages to protect hearing but allows normal ambient audio to pass through. Great use for protection against single shot, explosions, automatic rifle fire, artillery, impulse & impact noise. FEATURES: Helps guard against hearing damage caused by automatic fire and single gun shots, artillery fire and explosions, reducing them to safe levels, less likely to cause long term damage. Automatically engages to protect hearing. Still allows for ambient audio. Proprietary material for long wear comfort. Includes key chain aluminum transport/storage case. No batteries required. Two sets of ear inserts included.