Vivitar Filters are manufactured from high-quality solid optical materials. Each individual filter is heat-treated to avoid any rare movement or distortion. Our CPL filters remove unwanted reflections from non-metallic surfaces such as water and glass. They also improve color saturation, clarity and contrast. This threaded filter is often used to increase the contrast and saturation in blue skies and white clouds. Vivitar"s circular polarizing filters do not affect the overall color balance of a shot, and they will provide protection for your lens while shooting. Vivitar filters are perfect for digital SLR cameras or traditional 35mm SLR applications. The number on the filter you need will depend on the thread size of your lens. For example, the kit lens which comes with the Canon Rebel XT is 58mm, so you would need a 58mm filter.