1: Before purchasing a GPS tracker, please note that this product can only be used outdoors when GPS signals are detected. It cannot be used indoors or in places where GPS positioning cannot be obtained. Before purchasing, you can use mobile navigation to check if the GPS signal is normal,
2：Search ‘Action Tracer’ in APP Store or Google play
3：Regarding the selection of tank size: Chest size data can refer to: S/80-（31-34inches）86cm, M/85-96cm（33-38inches）, L/90-100cm
