This app, Gmate® ON is designed to help diabetics measure their blood glucose. You would need an additional device that is connected to Android SmartPhone to test your blood glucose as Gmate® ON will show you. You would need to buy Blood Glucose Meter named Gmate® ON that is connected to Android phones to test your blood glucose as Gmate® ON will show you. This application is compatible with Android phones having OTG(on-the-go) function, specially for Samsung Galaxy S2, S3, S4, S5, Note,