Real-time battery monitoring of up to 4 devices , Monitors can be combined for 24V, 36V and 48V systems (One monitor required per battery), Stores and displays historical data, Tests vehicle cranking and charging systems, Alerts sent to mobile device, Auto sychronisation (within 10m range), Free app for iOS and Android, Click here to download the Manual App Name:Matson Monitor , Average Current:1.5mA , Bluetooth® Name:Matson Monitor , Bluetooth® Version:4.0 , Dimensions:5.5 x 3.7 x 1.6 (cm) , Input Voltage - DC:6-20V , Operation Temperature:-40C to 90C , Reverse Polarity Protection:Yes , Short Circuit Protection:Yes