Orion 5525 2-Inch Multiple 4-Filter Wheel Anodized aluminum filter wheel conveniently allows switching of up to four 2" astrophotogrpahy and/or eyepiece filters Essential time-saver for tri-color astrophotography with large-format monochrome CCD cameras T-threads on the camera side of the filter wheel allows secure, threaded attachment to most astrophotography cameras Filter wheel includes 2" nosepiece for easy attachment to any 2" telescope focuser or accessory Helps protect your imaging filters from dust , dew, and scratches during use and when idle