Adopt high quality digital tube display range DC 2.4~30V can work for 3V 5V 9V 12V 24V etc; With standard wire convenient to connect car electromobile motorcycle inside curcuit with reverse protection function; With fine tuning function Max. input voltage 30V; Low voltage start red 2.4V yellow 2.5V green 2.6V blue 2.8V; Convenient for lithium battery and 18650 battery users etc; Technical parameters: Working voltage: DC 2.4~30V (with reverse protection function) detection voltage: DC 2.4~30V; working current: <30mA; 0.6" 3-digit Nixie tube; Limiting operationg condition: Min. working voltage: 2.4V; working temperature: -10~65'C; working humidity: 10~80% (No condensation); Working air pressure: 80~106KPa (no direct sunshine); Good stability; High precision measurement; Power supply adopt polarity protection circuit