Abstract: An improved measuring instrument for use with drawings employing different scales with indicia thereon; wherein, the measuring instrument includes a pair of elongated first and second instrument member arms having top walls and bottom walls and having opposite ends wherein one pair of ends are adapted to be releasably and pivotally connected to one another. The measuring instrument further includes a rotatble ratchet connection assembly associated with the first and second instrument member arms for captively but releasably engaging the first and second instrument member arms in both an L and an inverted L configuration. The tops walls of the first and second instrument member arms having beveled edges with indicia thereon, for preventing the indicia from engaging the measured or drawn surfaces when in use; and the bottom walls of the first and second instrument member arms having inclined planes with indicia thereon for preventing the indicia from engaging the measured or drawn surfaces when in use.