The Cassini Color Filter Wheel is another innovative device for telescopes from Cassini. Filtering out certain bands of light can be very useful when observing astronomical objects. Normally to use filters with your telescope you would have to thread the filters on and off of your eyepieces as you are use them. With the Cassini Color Filter Wheel you simply switch filters by rotating the dial on the Cassini Color Filter Wheel. The C.F.W. has three (3) filter settings: nebula planetary and clear. The nebular filter is great for filtering out light pollution to bring out the details of nebulae under a dark sky. The planetary filter is great for viewing the moon and planets by increasing contrast. This will help bring out dark surface details on Jupiter and Saturn darkens the maria on Mars and improves visual detail when viewing Neptune and Uranus. The third slot is empty to use an additional filter of your choice or can be left empty so objects can be viewed normally without having to remove the Color Filter Wheel. The filters are universal 1.25-inch threaded filters so you can switch them out with other filters for more usability. Format: 1.25 Brand: Cassini Model: CFW Color: Black Requires batteries: No Body material: Metal plastic Weight: 5 ounces Dimensions: 2.5 inches long x 3 inches wide x 3 inches high