The 9817-6-K Stability Series Center Mirror Mount builds upon the New Focus™ tradition of manufacturing outstanding kinematic mounts that use the best Hex-hey actuated adjustment screws and sapphire seats. This Black Anodized 1.0 inch (25.4 mm) diameter mount has a unique retention system for 6.35 mm thick mirrors that provides further performance enhancements. Designed originally for precision UV beamsteering applications in the demanding UV semiconductor capital-equipment industry, the retention system optimizes stability while minimizing wavefront distortion, ensuring that the mirrors are truly flat and rock solid. Mirror installation and removal is simple and fast, requiring no adhesives. This center mount featuring an OEM frame with two 8-32 (M4) clearance mounting holes per side minimize rotation when you secure the mount.