Electronic Hearing Protector with Bluetooth Click HERE for more information! EXTERNAL MICROPHONES for situational awareness. BLUETOOTH WIRELESS TECHNOLOGY for calls and music. NOISE REDUCTION RATING (NRR) OF 26 dB (26 dB with hard hat). DURABLE RECESSED MICROPHONES help prevent damage and reduce wind noise. IDEAL FOR TEAMS OR GROUPS of workers who need to communicate on the job site while helping protect their hearing.