The GB50 Granite Base Plate provides surface flatness to within 2 μm and features 3 point mounting to compensate for non-flat optical tables. Edge handles facilitate handling and locating the base plate on the work surface. They can be used to mount Ultra-Precision XM Series Linear Motor Stages on English and metric tables. For critical positioning applications requiring tight positioning accuracy and repeatability of a motion system, flatness of the mounting surface becomes a major factor. Polished granite surfaces are among the flattest, commercially available structures.