Features of RPM Digital Tachometer Lutron DT-2230: Versatile 2-in-1 design combining both photo and contact tachometer functions. Photo tachometer features a laser light detection source with a long measuring distance of up to 1.5 meters, ideal for RPM measurement in hazardous or hard-to-reach areas. Offers a wide measurement range from 0.5 to 100,000 RPM with 0.1 RPM resolution for readings below 1000 RPM. Built with a microprocessor-based circuit and crystal time base to ensure high precision and 0.1% accuracy. Bright, easy-to-read LCD display provides accurate RPM readings without guesswork while conserving battery power. Equipped with memory and recall functions that automatically store the last, maximum, and minimum measurement values. Designed with durable, long-lasting components and a strong ABS plastic housing for nearly maintenance-free performance. Includes an RS232 PC serial interface for convenient data transfer.