What is a measuring jug?

1. You fill it up with liquid and then.

2. Then what number it is on that is how many litres or millerlitres.

3. Some mesureing jugs have line the first line is 250 millerlitres than 500 millerlitres then 750 millerlitres than 1 litre. See how the numbers are adding by 250 millerlitres.