These paper filters are designed by Hario for use with the Hario V60 Coffee Dripper. They are designed to fit perfectly inside the Hario V60 cone and filter out unwanted particles to give you the delicious, clean cup that the Hario V60 pour-over is known for! The filters are available in three sizes - make sure to pick the correct size for your coffee dripper. The 03 size also fits the Chemex quite snuggly and makes a nice alternative to Chemex filters.