Astromania 2" Superior Quality Multiple 5-Position Filter Wheel For Telescope - allowing you to image without any reflections or stray light Filter positions indicated by the numbers 1-5, takes any standard 2" filter. It's very sturdy aluminum housing makes it also suitable for heavy cameras, accessory-side T-2 and M48 threads. This 2" filter wheel lets you use up to 5 different filters and change them within just a few seconds, you can also leave your filters mounted in the filter wheel, as they are optimally protected from dust and damage there. The telescope side of the filter wheel comes supplied with a 2" adapter, allowing you to quickly and easily attach it to your focuser. The very short design also permits the use of devices with short back focus such as Newton or Dobson telescopes. The filter wheel interior is absolutely light-tight - allowing you to image without any reflections or stray light. It's construction is impermeable to light and thus ensures reflection-free astrophotography. Please note: your focuser will require 20mm of inward focusing distance from the normal focus position to compensate for the thickness of the filter wheel. Use the supplied hex key to unthread the four socket head screws of the back panel of the filter wheel assembly. Be sure to place the screws in a safe place so they do not become lost. Once four screws have been removed, gently separate the back plate from the filter wheel. Install the 2&#034; filters of your choice into the tray simply by threading them into the filter tray. You may wish to note the number designation of each installed filter for convenient reference during use. You may find it useful to leave one of the five threaded filter locations empty, providing an unfiltered option for viewing or imaging. Once you have installed all the filters you wish to use, carefully place the filter tray back into the wheel assembly. Be sure the small plastic tab fully registers with the central hole of the wheel assembly so that it clicks into place. Position the rear plate so that the opening is aligned with the opening of the front plate. Complete installation by reattaching the rear plate of the filter wheel assembly with the socket head screws. If you are installing an individual filter or swapping one filter for another, you can avoid partial disassembly of the filter wheel. To install an individual filter, unthread the 2&#034; connector and nosepiece from the assembly to expose the internal filter tray. Rotate the tray so the desired filter location is shown. Install the 2&#034; filter by placing it on the filter tray and rotating it clockwise with your fingertips. Astromania 2&#034; filters feature a knurled rim which will prove helpful for this type of installation. Be careful not to touch the actual filter surface. Note: individual filter installation without disassembly may not be convenient for all users, especially those with large fingers!