Bluetooth: Bluetooth 5.2 Bluetooth protocol: A2DP hands-free configuration (HFP) AVRCP Frequency range: 20 Hz – 20,000 Hz Charging time: full charge time for glasses: about 90 minutes Battery type: lithium ion polymer lithium battery Charging interface: the charging box is connected to the charger through the charging cable, the glasses are put into the charging box, and the glasses are charged wirelessly through NFC Battery capacity: 85mAh (typical value) Music playback and call duration: up to 5 hours listening to music; up to 3.5 hours voice call Microphone: Two silicon microphones on the main ear, support for uplink noise reduction Horn: 1 moving coil unit on the left and right (0825) Temperature: working temperature: 0℃~35 ℃; charging temperature: 0℃~35 ℃; storage temperature: -20℃~45 ℃ Waterproof rating: support dust and water resistance (IP54) Remarks: This product is not professional waterproof glasses, and the splash-proof, water-proof and dust-proof functions are not permanently effective. The protective performance may be reduced due to daily wear and tear. Do not charge the glasses when wet; please refer to the user manual for cleaning and drying instructions.