Precautions: Android fans only need OTG-enabled mobile phones! Stress the statement! The power bank cannot be used! Some phones have OTG function but need to be turned on in the settings. You can use it after turning on the OTG key, especially OPPO, VIVO, Huawei, etc., depending on the situation! This product is rotated by the power output of the mobile phone, which has a certain loss on the battery. It is not recommended to use it for a long time.