Oxygen whitened paper. Disposable basket type filters approx. 3-3/16 in. base x 2-3/8 in. deep (8.1 x 8.0 cm). Tru Brew Coffee Filters are manufactured from the highest quality filter paper. This paper is bleached through an oxygen process which reduces the amount of chlorine, and thereby provides a more environmentally responsible product. It meets all FDA guidelines of paper used for food contact, and is made of 100% virgin fiber. These filters trap grounds and sediments for clean coffee without bitter taste.