About Bluedio: Bluedio is a pioneer in portable audio device, providing solutions to professional audio and wireless communication. Bluedio always strives for perfection, fashion and simplicity, focusing on revolutionary innovations. So far, Bluedio has owned over 30 patents, highly praised by consumers over 34 countries. Pairing Tip: When pairing, you need to make sure the headphones have entered pairing mode, here is how to enter pairing mode: When the headphones are off (If not, turn off the headphones first), press and hold the Power Button until you see the blue light stays on (instead of blinking). Specifications: Bluetooth version: V5.0 Profiles: A2DP, AVRCP, HSP, HFP Drivers: 57mm Impedance: 16 Frequency response: 20Hz -20KHz SPL: 110dB Operating distance: up to 32 ft. (no obstructions) Bluetooth music time: about 40 hours Bluetooth talk time: about 45 hours Standby time: about 1625 hours Fully charged time: about 2 hours Warranty Information: 1 year warranty from the date of purchase. In the box: Bluedio H wireless headphones Storage bag for headphone Micro USB charging cable 3.5mm Audio cable User manual