The Expedition Brewer was designed to use cone filters. Not those V-shaped Melitta filters you find at the grocery store, but a true cone. This is our preferred filter because it has a good flow rate, doesn't require a pre-rinse, and won't add a paper sack taste to your coffee. 100 bleached filters, size O2 if that helps. Pack some in the Expedition canvas. Or drop one in the V60 on your Launchpad. The whole pack will slide right into your Filter Crib. One size fits all.