Headphone Style Over-Ear Sound Isolating Yes Built-in Mic Yes BT Version 5.1 Work Distance 10m Charging Time About 2H Playing/ Talking Time About 8H Standby Time About 40H Speaker Size 40mm Frequency Range 20~20000Hz Battery 3.7V/300mAh Cord Length 250±5mm Soft & Breathable Earpads The breathable and comfortable oversized ear cups will completely cover your ears, providing an extremely comfortable experience for long listening sessions without worrying about sore or sweaty ears. Up to 40 Hours of Battery Life With a 300 mAh battery capacity, it only takes 2 hours to fully charge for up to 40 hours of battery life, 8 hours of uninterrupted music playback, and all-day listening to your favorite audio content. Reliable 5.1 Bluetooth Technology The new bluetooth 5.1 technology provides a more stable and faster connection. MUCRO wireless earphones are compatible with most electronic devices such as smartphones, tablets, laptops, smart TVs, etc. It supports connection up to 33 feet (10 meters).