The Door Stud is a hands-free device designed to simplify installation of doors on the jobsite. Made from 12-gauge steel, the Door Stud will accept a 1 3/8- or 1 3/4-inch door weighing up to 300 pounds and will hold a door slab upright in a jamb opening at the precise location to scribe and set the hinges and the passage or lockset. Or it can be used to set prehung units into rough openings using shims or clips. Wheels allow you to quickly and easily move the door in and out of the opening, and adjustments of the wheel height allow you to plumb the door by leveling across the device. A pair works for a single door installation; two pair for a French door. Retail is about $270 per pair. Larger models that can accommodate heavier (up to 600 pounds) and thicker (up to 3 inches) doors are available. thedoorstud.com