Product Features:Using Bluetooth 5.1 technology, lower energy consumption, compatible with multiple protocols, fast transmission, strong anti-interference, and more stable signal. Compatible with Bluetooth devices such as mobile phones, tablets, and laptops.With ergonomic headwear design, comfortable and breathable sponge, all-inclusive ear design, memory rebound soft and skin-friendly, folded mesh earmuffs make it more comfortable to wear, fit, and breathable without pressing the ears or leaking sound. Folding design, easy to carryHigh-quality clear sound and deep bass give you a great listening experience. Built-in microphone supports voice calls.Built-in 300mAh lithium battery can support nearly 12 hours of wireless use time. At the same time, it supports 3.5mm audio cable link, so there is no need to worry about the headphone running out of power.Specification:Frequency response: 20~20KHzMaximum output power: 20mWWorking range: 810mBattery voltage: 3.7VBattery capacity: 300mAhBattery charging voltage: DC4.2-5.5VCharging time: 2HWorking hours: 12HImpedance: 32 ohmSensitivity: 110+/-3dBSpeaker diameter: 40mmInterface: Type-c