Stack Professional Stepper Motor precision auxiliary instruments combine digital microprocessor accuracy with a high-precision stepper motor needle movement, to provide a new level of accuracy and reliability in 52mm gauges. They combine the durability and readability of 270″ mechanical gauges with the easy installation and safe operation of conventional electric gauges. The 270″ dialface together with the new white LED backlighting and illuminated needle ensure excellent readability day or night.