3M Peltor WS ALERT X Headset is a Bluetooth headset with noise-cancelling boom microphone that connects to your mobile phone for hands free calls and streaming in noisy environments. The headset has a level-dependent function for ambient listening, and it syncs to a mobile app so users can easily set-up and adjust the headset, Attenuating hearing protector comes in two models: headband or a safety helmet attachment (MRX21P3E4WS6), Bluetooth technology for connection to an external Bluetooth device allows for hands-free talking and streaming, Noise-cancelling boom microphone for clear speech transmission in noisy environments, Level-dependent function for ambient listening to help promote auditory situational awareness, Connection to an iOS and Android compatible mobile app, 3M Connected Equipment, to more easily set-up and adjust the headset. The app is available to download from App Store and Google Play. Mobile app allows you to receive reminders when to change replacement cushions (hygiene kit) and choose the frequency of these alerts, Replaceable cushions (hygiene-kit) and replaceable covers so you can change to your own choice of colour, Push-to-Listen feature to listen to your surroundings easily and instantaneously, Voice guided feedback after setting adjustment. No need to remove the headset for any adjustments, The headset will automatically turn off after four hours of non-use to save battery life, 2 x AA Alkaline Batteries (or optional NiMH rechargeables), Operating time: Approx. 78 hours (Bluetooth streaming and level-dependent) SNR 30 dB.