Tiffen 4x4 Polarizer Filter is a polarization filter glass for use in a matte box. This is for square filters that are not placed on, but in front of the lens. Polarization filters improve color and contrast by decreasing reflected light. Reflected light is often displayed as a whitish glare that washes the color of an image, like when photographing or filming through a window or water surface. A polarization filter corrects this issue and creates deep, dramatic blue skies. Color saturation in general, but especially outdoors, can be significantly improved by using a polarization filter. Tiffen filters use the ColorCore technology, which uses laminated glass to achieve uniform colors and density, even after polishing the glass. As the polarization effect bends the light, the filters work best at a 90-degree angle with the sun. The filter is 101.6 x 101.6 x 5 mm and fits the matte boxes we rent out. The filter factor is 2.5x, which means that it lets in 1.3 stops of light less. The filter glass weighs 300 grams and comes in a protective sleeve.