This is a  Newport New focus 9811 Mirror Mount,  1 in., 3 Knobs. This mount is for 11" optics such as mirrors and lenses. it comes with  a mirror and 1" post.

This Newport New Focus 9811 Corner Optical/Mirror/Lens Mount is the ideal addition to your laboratory equipment. With a sturdy design and three adjustable knobs, you can easily maneuver your laser or microscope to the desired position. Perfect for physical, medical, and biological laboratories, this mount is a must-have for any researcher or scientist. Crafted with precision and made to last, this mount can hold up to heavy use and constant adjustments. Its versatile design allows for easy compatibility with various laser and microscope models. Add this Newport New Focus 9811 Corner Optical/Mirror/Lens Mount to your lab today and experience the convenience and precision it offers.