1.Built-in 32G SD memory card : There are more than 2600 music storage for you with the bone conduction earphone. 2. The IPX8 bone conduction headphones works well In the shower or swimming pool. 3.The headphones fit for Bluetooth-enabled smartphone or tablet. 4.IPX8 level professional waterproof non-inductive wear comfortable and passionate. 5.Beyond imagination is lightsome, circular chamfering type design, movement more without oppression. Material: ABSandPC Color: Black Battery: 180mAh Wireless working range: 10 meters Input voltage: 5V Waterproof performance: IPX8 Notes: 1. Battery must be fully charged for the first use of headphones. 2. Do not swim for more than 30 minutes each time 3. If you don't use it for a long time, please charge it at least once a month. 4. After each exercise, clean the water from the surface of the headphones, especially the charging position magnetic, and clean it in time to prevent sweat and salt water corrode the loading port and affect life useful of the product. 5. Please use a charging head with an output of 5V1A or less.