24dB Noise Reduction Rating (NRR) with stoppers inserted * Lowers potentially dangerous noise levels above 85dB * Hear safe sound levels (with stoppers out) as if you weren"t wearing ear plugs * EarLock? by SureFire® retention ring utilizes seven contact points to lock earpiece in place and fit the same way every time; soft, double-flange stem provides secure seal and all-day comfort. * Low-profile design allows you to keep them in place while wearing a mask, helmet, hat, or while using phone, headphones, or supplemental hearing muffs