Visual and photographic filters play a big role in how we see or capture the objects in the night sky. There is a filter to enhance every situation. Photographic color filters are an essential accessory to the astrophotographer, while visual color filters help to bring out amazing detail to the human eye. There are broadband filters for boosting contrast or reducing the effects of light pollution and narrowband filters for concentrating on very specific wavelengths of light, including those only our cameras can see. There is also a wide range of sizes available. The size you'll need is usually determined either by the size of your eyepiece barrel (typically 1.25" or 2") or the size required by your filter wheel, carousel, or slider. TPO has divided these filters among those two categories by size to make it easier for you to find exactly what you need.
At the moment TPO only has one retail provider, Oceanside Photo & Telescope. If you would like to buy any TPO telescopes, eyepieces, filters, diagonals, or other telescope accessories feel free to call 1-800-483-6287 and someone will help you with whatever it is you are looking for.