Product use Description: 1. Bluetooth connecting,bluetooth v4.0 EDR communication protocal could connect 4 anti-lost devices at the same time. 2. Powerful function,both-way junction(smartphone anti-lost devices could control each other). 3. Extraordinary working hours,our devices have ability to work about 6 monthes by 3V CR2032 button battery power supply,don't need to replace the batteries frequently. 4. Intelligent alarm,when the anti-lost device exceeds the set bluetooth range,the mobile phone and the anti-lost device will alarm at the same time; when the anti-lost device is disconnected,the map location can be checked on the mobile phone. 5. Anti-nuisance function,it can be set to mute for a certain period of time to prevent interruption during work and other important times; Specifications: Compatible system: Apple IOS 9.0 or above / Android 9.0 and Bluetooth 4.0 or above. Communication Protocol: Bluetooth v4.0 EDR. Multi Task Management: one smart phone could manage up to 4 anti lost devices at the same time. Working Distance: about 50 m. Battery Efficiency: CR2032 button battery,lasting up to six months. App Voice: English ?????? The product APP can be downloaded for free by scanning the QR code or finding iSearching in the Apple/Android system store.