1. Multifunctional USB charger with three integrated capabilities: it measures the car battery voltage, displays the car temperature, and provides USB charging for mobile devices. 2. Car battery voltage meter: real-time voltage readings help prevent excessive electrical draw that could affect engine starting, supporting reliable vehicle operation. 3. Temperature meter: detects the interior car temperature to help you maintain a comfortable cabin environment. 4. USB charger for mobile phones: convenient and fast charging for your phone and other USB-powered devices. Use scenarios - Daily commute: monitor battery voltage during regular drives, keep the cabin comfortable by checking interior temperature, and charge your phone through the USB port. - Long road trips: track electrical load to avoid battery drain, use the temperature display to manage climate for comfort, and keep devices charged on the go. - Vehicle maintenance checks: observe battery status as part of routine inspections to ensure electrical systems are within safe levels while driving.