It can check the vehicle cranking system automatically while engine is starting, and also check the recharging system. It also can list the time of each driving anf will alert your smartphone if some data abnormal, and also has the short-circuit and reverse connection protection. This battery monitor suitable for the 12 V vehicle batteries and you can review the historical data graphically. With the function of data stored in battery monitor up to 35 days if out of sync, and it will automatic synchronization when enter BT . Receive notification of battery conditions when enter BT , which can save your time. Specifications: Material: plastics Average current: 1mA Voltage accuracy: ±0.02V Input voltage: 6~20V BT name: battery monitor Short-circuit protection: built in Reverse connection protection: built in BT: 4.0 Operating temperature: -40~85 APP keyword: BM2 Available: Android 4.3 and Later IOS: IOS 7.1 and Later Item size: 55 * 35 * 15mm / 2.2 * 1.4 * 0.6in Package size: 170 * 135 * 20mm / 6.7 * 5.3 * 0.8in Package weight: 85g / 3.0ounce Packing list: 1 * Battery Monitor