Laser Photo Tachometer Features:

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: 3x1.5V AA battery(DT2234A)
　　　　3x1.5V AAA battery(DT2234C)
Time Base: 6MHz Quartz crystal
Time Base Accuracy: 10x10-6(0~50°C)
Power Consumption: Approx 40mA
Dimension: 160Lx72Wx37H(mm)(DT2234A)
　　　　　 184Lx76Wx30H(mm)(DT2234C