This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

The thickness of paper is often measured by caliper, which is typically given in thousandths of an inch in the United States and in thousandths of a mm in the rest of the world. Paper may be between 0.07 and 0.18 millimetres (0.0028 and 0.0071 in) thick.
What tool is often used in measuring the thickness of paper?