The stage of a microscope is the part of the microscope where the specimen is placed for observation. It is typically a flat platform that supports the slides, and stage clips hold the slides in place. The stage is often equipped with a mechanical device that holds the slide and allows for precise positioning and observation under a microscope. A simple microscope stage contains an opening to admit light from the condenser, several mounting holes for a mechanical stage, and two clips that secure the specimen slide in place for observation under increasing magnification (changing of objectives) and for photomicrography. The stage is also equipped with a locking control that can fix the position of the stage. Both stages may be rotated with respect to the microscope body to facilitate framing during photomicrography. There are a wide variety of microscope stages that are designed for specific purposes, including stages equipped with auxiliary equipment for manipulating samples during observation, measuring systems that allow precise measurements to be made over very small distances, universal stages that allow measurements over many specimen angles, and other specialized stages that perform a myriad of unique functions.