with
millimetre divisions and numbers in
centimetres. Fully extended it measures 2 metres. In countries in which the metric system is used, the scale typically contains only a metric scale. The scale marks every millimetre with every 5th millimetre marked by a slightly longer line. Every centimetre is marked with an even longer line and a numeric label. Every 10th centimetre is usually predominantly marked. They might be referred to as yardsticks, metre-sticks or "inch sticks". In the United States, the marking is usually in
customary units (three
feet inches with
inch and fractional inch). Hybrid measures bearing customary markings on one side and metric units on the other also exist and are sometimes referred to as yardsticks, metre-whesticks or "metre rulers". The spelling meter vs metre varies by country, though metre is the official and most widely used spelling in English-speaking countries. Although not used as often, metre-sticks with only a metric scale can be found in the United States. For example, they are common in schools where there is a desire for students to become familiar with metric units, since the nineteenth century. They may also be used in American science labs. The folding carpenters'
rulers used in
Scandinavia are sometimes equipped with double measurements, metric and imperial on both sides, also functioning as a handy conversion table, accounting for its Scandinavian term: Tommestokk/tumstock (
thumb (inch) stick), a term with the same meaning that is also used in
Dutch: duimstok. Metric only carpenter's rulers are however common. ==Application==