The 9173-M Valu Pedestal Periscope kit include all the mechanical parts necessary to easily build your periscope-all you need to add are the 25.4 mm mirrors. Each periscope kit includes two 6 in. optical pedestals for sturdy mounting, two of our pedestal clamps to adjust the mirror to any height, two Valu mounts, and a holding fork. We also include two 45° adapters, which simplify alignment by letting you center the beam on both mirrors. Metric threads.