The Optimate O-100 V3 is a smart 2400mA USB charger, with standby mode & vehicle battery monitor. The portable & compact SAE to USB charger for safe & fast charging for any USB device, including your phone, camera or GPS. Connects to battery cable with industry-standard SAE 2-pin connector Has 1 USB-A connection Charging current adapts to the connected device for safe charging. Creates a weatherproof seal against imported USB cable, or ‘drive-safe’ cap seal when not in use Worry-free phone, camera or GPS charging in any weather condition! - Built-in protection disables USB charging & prevents draining your vehicle's LFP (LiFePO4) or AGM (Pb) battery. - Restarts when the vehicle's engine starts up. - Monitors and displays the battery status of the parked vehicle. - Indicates that the battery is ‘ready to start’ with a flashing LED!