Provides universal adjustment in both horizontal and vertical planes. For use with all Starrett Test, Back-Plunger, AGD, Dial and Miniature-Dial Indicators. Accommodates similar indicators of other manufacturers. Powerful, permanent magnetic base holds firmly to steel or iron surfaces - horizontally, vertically, upside-down. Push-button turns magnetic force on or off for quick, one-hand set-up and take-down. V-step adapts base to horizontal or vertical arbors and chucks. Black wrinkle finish on non-working surfaces.