Your hearing is always safe with these FireMax muffs thanks to lightning-fast Sound Activated Compression (SAC), a rubberized, sound-dampening composite housing construction, and a noise reduction rating (NRR) of 23 dB. Plus, these IPX4 waterproof-rated muffs also feature an advanced digital audio circuit and full dynamic range HD speakers for clear, balanced sound via four frequency modesUniversal, Clear Voice, High Frequency Boost and Power Boostwhether you're on the job or enjoying some time at the range. The rubber Tacti-Grip headband with cooling gel earpads keeps long outings in warm conditions more tolerable, while the digital, soft-touch buttons ensure operation is both silent and intuitive. Powered by a 2,000 mAh lithium-ion battery that's 100% rechargeable thanks to the integrated USB-C charging port and an included charging cable, count on these muffs to deliver up to 200 hours of use while you're on the go. Auto shutoff ups the convenience factor, giving you one less thing to worry about. And, for added convenience, wearers can easily connect any of their mobile or smart devices using the 3.5mm audio jack.