3Mâ„¢ WorkTunesâ„¢ lets you substitute the noise of the jobsite or workshop with your favorite music. Stream music from your smartphone, tablet, MP3 player or other Bluetooth device. Bluetooth streaming lets you eliminate cords and use a simple dial to control your music. Voice Assist guides you to your favorite radio stations without having to remove WorkTunes from your ears and helps program up to 50 stations. Features simple button design controls, excellent sound quality, bass boost and improved reception. Upgraded technology and programming enables use in other countries. Earmuff hearing protector provides noise reduction rating of 25dB. Features a specially engineered headband for temperature control and all day comfort that fits with hats and caps. Soft, comfortable ear cushions. Voice Assist low battery indicator. Redesigned battery cover with hinge to minimize breaking. Enlarged center knob for easy operation.