Electronic ear muffs

1.Protect your hearing from harmful noises, but also allow you to hear normal conversation. 2.Weak sounds can even be amplisfied, so you hear them better than you would without electronic ear muffs. 3.Immediately attenuated the noises above 85 dB. 4.On/Off switch with volume control 5.Soft, wide and foam ear cushions and individually headband provide an even and consistent distribution of pressure around the ears for the best possible comfort. 6.Powered by two AA batteries (not included) 7. Approved by EN352-1,EN352-4, CE, ROHS, FCC, ANSI, PAHs-free and so on. NRR: 21dB