Photo Tachometer DT2234C (Laser) is applicable to the product departments of motor, fan, paper-product, plastics, chemical fiber, washing- machine, automobile airplane, steamer etc. Built-in laser for non-contact measurements up to 3.5 feet away. Narrow beam laser for accurate non- contact RPM measurements Microprocesser based, high resolution and accuracy. Feature: Wide measuring range and high resolution Measures exact RPM with no guessing or errors Memorized the last value, max. value and min. value Low battery power indication Specification: 5 digits 18mm (0.6) LCD Accuracy: ±(0.05%+1 digit) Sampling Time: 0.5sec(over 120RPM) Range Select: Auto-Ranging Memory: Max. value, Min. value, Last value Measuring Range: 2.5~99,999RPM Resolution: 0.1RPM(2.5~999.9RPM) 1RPM(over 1,000RPM) Detecting Distance: 50~500mm Battery: 4x1.5V AA battery (Not be included because air post prohibition) Time Base: 6MHz Quartz crystal Time Base Accuracy: 10x10-6(0~50°C) Power Consumption: Approx 40mA Dimension: 184Lx76Wx30H(mm)(DT2234C) Package: airbubble envelop 1 x DT2234 tachometer; 1 x black plastic gift box.