The 4 x 5.65" Cinema Filter Cartridge from Revar Cine is made from an injection-molded poly-nylon material that is impact, pressure, and temperature resistant. This cartridge has a small latch closure to keep dust and dirt away from your filter. Internal rail guides keep the filter away from the interior sides of the cartridge and off of flat surfaces while allowing you to easily remove your filter without touching it. If dirt or debris gets into the cartridge, the rail guides will keep it away from the filter. Weak magnets in the cartridge allow you to loosely stack multiple cartridges. The specially designed screws can be removed to thoroughly clean the inside of your case.