Features: Alternator state check. Battery state check. Battery overload display. 6-LED display, clearly present the alternator and battery state. Two testing clips for safe and easy operation. Small size and light weight, convenient to carry. Fit for car, motorcycle, etc. Suitable for :12V lead acid batteries, hardtop batteries, discharge batteries and maintenance free batteries heavy duty insulated clamps. Easy and safe to use, no sparking. With a good chip inside, not easy to get hot on the surface. 6 LED Lights: Alternator state check: First light (red): Fault Second light (green): Good Third light (green): Full Battery state check: First light (yellow): Middle Second light (red): Low Third light (green): OK.