Abstract: A marker device that clips onto a page, for example, has a spring between proximal ends of a pair of similar congruent leaves so as to spread the proximal ends away from each other and press corresponding opposite distal ends toward each other. One leaf has graduations on it constituting part of a scale or ruler. A third flat straight leaf is connected to one of the pair of spring-biased leaves in such manner that the third leaf can slide and extend or contract relative to the one leaf. The third leaf has graduations that form a continuous measuring scale in conjunction with the graduations on the one leaf when the third leaf is fully extended.