Abstract: A device for preparing to mount a wall fixture includes a main base having opposed first and second ends and a first auxiliary base having a substantially similar configuration. The first auxiliary base is coupled to the main base and movable between a closed configuration in which the first auxiliary base is positioned substantially atop the main base and an open configuration in which the first auxiliary base is linearly adjacent the main base. The main base and first auxiliary base each define a slot extending longitudinally between respective first and second ends. Each base includes a marking member situated in a respective base slot and slidably movable therealong. Each base includes a respective locking assembly for securing a respective marking member at a desired position along a respective slot. Each marking member includes a pointed distal end for making a starter hole when depressed against a wall surface.