These adjustable mirror mounts are designed for use in vacuum systems with a conflat 2.75 flange and can accept a 1.0" OD optic. The optic is held in place between a large diameter o-ring and a brass backing. The 3 adjusment knobs work against the brass backing, allowing for easy variation in the optic's angle without the need to break vacuum. The purgable version comes with a tube welded into the flange, allowing gas to be admitted directly to the optic situated in the mount. Optional mirror precision actuators are available, which allow absolute and precise control over the angle of your mounted optics. This is the Mount ONLY.