Item smart tracker size is  1 7/10" L x 1 1/2" W x 2/5" H,it's a kind of Low-energy product.It can chain user's easy-lost & valuable belongings (such as keys, handbags etc.), kids or pets together with smart phones through specified App software within a setting Bluetooth connection distance. In the effective distance it can realize the functions of anti-lost, looking for smart phones, self-portrait and voice recording.