【Professional Grade Protection】: Professional Grade Industrial Protection is one of the best ways to safeguard your hearing. The safety helmet-mounted Bluetooth earmuffs are certified by ANSI S3.19 NRR 27dB and CE EN352-1 SNR 32 dB 【Comfort and Protection Combined】: This shield hard hat-mounted electronic earmuffs with Bluetooth and mic are crafted for both comfort and noise reduction during and after work. These noise-canceling Bluetooth earmuffs smoothly integrate into the dedicated side accessory mounting slots of UM ULTRAMAXX hard hat and safety helmet for a snug fit. Compatible with most safety helmets (except full brim hard hats) 【Stable Bluetooth Wireless】: With Bluetooth 5.3 technology, it offers a wider working range and a more stable connection. Seamlessly connect to your phone, computer, or tablet for easy control of music and calls on 【Long Battery and Hi-Fi Sound】: The low power consumption and a large 1000mAh battery guarantee all-day work without power failure. Comes with 3.5 mm AUX cable and safe charging via USB Type-C connector. Enjoy loud and excellent sound quality with high-quality microchips and Hi-Fi speakers wherever you are 【Easy Installation】: The earmuffs easily snap into the dedicated side accessory slots on most cap-style hard hats, safety helmets, and face shields. Easy to adjust and tilt UM ULTRAMAXX noise-canceling hard hat bluetooth hearing protection earmuffs with mic integrate seamlessly into UM ULTRAMAXX Hard Hat and Safety Helmet slots for a secure and comfortable fit. Compatible with most Safety helmets (not for Full Brim ones). Designed for Hard Hat Mounted, it uses Bluetooth 5.3 technology for wider range and stable connection. Connects to your phone easily for music and calls. Allows hands-free calls without removing. To confirm fit, your Hard Hat should have 30mm long and 5mm wide holes on both sides. Easy to install, compatible with most helmets, fits well with UM ULTRAMAXX VOLTEK VENT series. It can be charged in 2 hours with a built-in rechargeable battery and standby time of 15-30 hours. Has a built-in mic for calls, boom mic for better quality in loud places. You can dismantle the boom mic if not needed. The package includes: Hard hat Mounted Bluetooth Hearing Protection *1, charging cable 1, boom microphone1, 3.5mm Cable *1, Manual *2.