Each unit comes with its own calibration certificate, which reports the measurement error of the unit at 2 points across its range.
Large LCD display
Automatic Min/Max Memory
Soft carrying case & 200mm of reflective marking tape
Display: 5 digits, 18mm high
Range: 2.5 - 99,999 RPM
Resolution: 0.1 RPM (2.5 - 999.9 RPM), 1 RPM (1,000 - 99,999 RPM).
Accuracy: 0.05% + 1 digit
Calibrated Points: 500 RPM; 6000 RPM;
Sampling Time: 0.8 sec.(over 60 RPM)
Detecting Distance: 50 to 200mm (LED), 50 to 500mm (Laser)
Time Base: Quartz crystal
Operation Temperature: 0 to 50 degree Celsius
Battery: PP3 9V (not included)