Starrett 2900-3-1 Electronic Capacitive Indicator, Standard Features English, 1" Graduation Range, 0.0005" Resolution True Absolute Sensor Technology  remembers position and zero set point even during battery replacement. Cannot be over-sped into failure. Intuitive design and layout  easy to learn and use Positive, tactile-feel button activation IP67 protection against dirt, dust water and coolant to withstand hostile shop environments Long battery life