A panel or dash display capable of reading sensor output voltage to help determine filter restriction or other conditions being monitored by a sensor. As voltage increases, a light bar progressively illuminates until reaching maximum condition or full illumination of the light bar. The unit has memory, and will remember the highest condition even if power is turned off.  The last LED flashes when maximum condition is reached. The display can be adjusted to off, dim and bright settings. It can be reset to zero by pushing the reset button.  Display will accept 6 to 30 volts input, and it can provide sensors with a regulated 5 volt signal. Available in square and round versions.