Come and see our amazing products. As long as the item is out of range (Usually the Bluetooth-compatible range is around 5-15 meters indoors and 50 meters the most in an open area), your smartphone and this keys finder will both beep to alarm you. It is not easy to leave behind your keys at the restaurant again. Once your items went out of range and were lost, the App will automatically record the last place where this key finder is disconnected from your phone, so you can speculate approximate location based on the last recorded spot shown in the App map to find your missing items. When you get close to your lost finder in the connection range, the finder and app will automatically reconnect, then you can call your items.Long press the button on the finder until you hear two beeps to turn it on (the same way to turn off). Pls confirm further with us if any query about packing info, inventory status and time schedule.