Manufactured from high quality, heavy weight paper, so the water flows properly through coffee/tea. Uniquely designed for strength so the sides are taller and you don't end up with overflow and grounds in your coffee. Produced using an elemental chlorine-free (ECF) bleaching method. Coffee Maker Size: 12 Cup; Material(s): Paper; For Use With: BUNN® 12 Cup Commercial Brewers; Shape: Flat Bottom.