This key finder is controlled by sound, by whistling, the key finder will make a sound after sensing it, letting you know its location.So it can help you to find the lost keys, remotes, purse, eyeglass, canes and other easily lost items quickly. Design with LED light, let you use it as a temporary flashlight in the dark. Light up the keyhole when returning home at night for easy unlocking.Equipped with a link, you can put it directly on the keychain. Easy to use, after turning on the switch, you can find it by whistling within the searchable range.