Electronic Ear Muff, Noise Reduction Rating NRR 23dB, Earmuff Style Over-the-Head, YellowBattery Type (2) AA, Standards ANSI S3.19-1974, Includes Batteries For 140 Hours of Use, Pair of Hard Hat Adapters Sound Amplification Ear MuffsImpact Positioned microphones provide more natural hearing. Feature AUX signal input and automatic shutoff. Include 2 AA batteries.Meet ANSI S3.19-1974