The Safariland Pro Impulse In-the-Ear Hearing Protection is a reusable, high-end earplug that offers users a Noise Reduction Rating (NRR) of 33dB. An enhanced contoured shape is easy to insert, and the proprietary material offers superior long-wearing comfort while patented IMPULSE Filter Technology automatically engages to protect the user's hearing from loud noises but allows normal ambient audio to pass through to carry on normal conversations. Plus, a key chain aluminum transport/storage case and 2 sizes of ear inserts (1 pair of filters) are included. No batteries required. Enhanced contoured shape Proprietary material for superior comfort Patented technology automatically blocks loud noises 33dB NRR No batteries required