• Measurement range: 20cm/7.87"; Minimum scale: 0.1mm/0.004". • Material: Transparent PET plastic, resistant to deterioration and unbreakable. • Thickness: 0.1mm/0.004". • Metric scale on one side and imperial scale on the other for accessible measurement. • Includes R angle scale to measure the radius of rounded corners. • Different size width lines in the middle to measure line thickness. • Ideal for factories, research institutes, measurement rooms, and workshops. • Useful for measuring product areas, calibrating measuring instruments, measuring the reduction ratio of photographic films, and detecting sizes in optical projection maps. • Includes 1 transparent ruler. • The 0.1mm scale should be used with a magnifying glass for accurate readings.