Digital panel meters are digital displays intended to be mounted in a panel, such as a control panel . They typically read some type of input, be it a voltage, current, or resistance, and display its value digitally. https://youtu.be/aE-FbMA9sIg Specification: Model: MT4Y Brand : Autonics Various input/output (default: indicator) Input: DC voltage, DC current, AC voltage, AC current Output: RS485 communication output, Low-speed serial output, transmission (DC4-20mA) output, BCD dynamic output, NPN/PNP open collector output, relay output Maximum allowed input: 500VDC, 500VAC, DC5A, AC5A Display range: -1999 to 9999 High/low-limit display scale function AC frequency measurement (range : 0.1 to 9999Hz) Various functions : Monitoring peak display value function, display cycle delay function, zero adjustment function, high display correction function, transmission (DC4-20mA) output scale function etc. Power supply: 12-24VDC, 100-240VAC 50/60Hz Package includes: 1 x Autonics MT4Y Digital Multi Panel Meter