Designed for shooters, hunters and other outdoor enthusiasts, these premium earbuds combine an impressive 24 dB NRR (Noise Reduction Rating) to shield your hearing from gunshots and other loud noises, while integrating Bluetooth 5.0 for seamless connectivity through the Walker&';s Link app. And at the end of a long day at the range, the duo&';s built-in lithium batteries, which provide up to 14 hours&'; worth of runtime, are easily recharged using the included micro-USB cable, so you always have appropriate hearing coverage juiced up and ready.Features : Four Frequency Modes, Including Universal, Clear Voice, High Frequency and Power Boost Split Second (SAC) Sound Activated Compression Protects Hearing Three Sizes of Locking Fins, Silicone Foam Tips, and Silicone in-ear Tips for Overall Sound Enhancement and Comfort