Two models of Mounts with 0-28 mm and 22-52 mm aperture are used for holding and adjustment about two angular coordinates of orthogonal or round optic. A clamping bar is used to fix optical elements, ensuring gentle but firm clutch. Highly Stable Precision L-shaped Optical Mounts are designed on the basis of two angular adjustment mounts, and are produced of steel with black chemical finishing. Special figure spring is used in these Mounts for two purposes: 1. It provides pre-loading against the tips of two precise driving screws for elimination of backlash. 2. It ensures the absence of the roll coordinate. The Highly Stable Precision L-shaped Optical Mounts have two M10x1 threaded mounting holes for mounting of the actuators. This allows to use all driving screws with these mounts. M6 tapped holes on the sides provide a wide variety of mounting configurations, either horizontal or vertical. A special L-shaped design of the Mounts provides for maximum clear aperture.