Chemex Bonded filters are specifically designed and manufactured to work best in their Chemex lines of brewers. The Chemex filters are a bit heavier construction that standard paper filters, and hold up well where others tend to fall apart and break! We recommend the Chemex square filters as opposed to the round filters, as they are a bit easier to grasp and work with. The Chemex filters are folded into a cone shape and easily fit down into the Chemex units.