A51 USB Charging Wireless Bluetooth HIFI Stereo Headset with Mic Feature: 1. Dynamic unit design, good audio analysis, no distortion of details, excellent immersive listening experience. 2. Choose professional internal magnetic speakers, add a bass diaphragm at the bottom, full bass, bright high sound, it will make you addicted to listening at once. 3. With a rigid, soft and thin composite diaphragm, it creates a rich and spacious auditory effect, and enjoys the presence of deep bass, clear midrange, and loud treble. 4. The ear shell is designed with a 15° tilt, the arm can be stretched in a large size, and it is equipped with soft leather earmuffs, which is skin-friendly, breathable and not stuffy, providing a comfortable wearing experience. 5. 40mm dynamic coil unit, with strong bass explosive power, such as clear and realistic sound quality and deep bass at the scene, presenting you with a different listening experience. 6. Fall in love with the dynamic and crystal-clear treble and the crisp and deep bass line, adding features to any song. Specification: 1. Bluetooth 5.0+EDR 2. Range: 10 meters 3. Speaker: 40mm Inside magnetic trumpet 4. Battery: 350mAh 5. Working time: up to 6 hours 6. Standby time: up to 20 hours 7. Box Size:19.5x20.8x4.9cm 8. N.W.：0.177kg 9. G.W.：0.321kg Packing list： Headset x 1 User manual x 1 USB cable x 1