The Pax 2/3 Screens work to avoid build-up in your Pax vaporizer oven. Since they serve as a filter for your vaporizer, they need to be changed regularly (after every 25 uses). Cleaning the screens is quick and easy, just place them in a pot of boiling water and wipe them dry. These screens are compatible with both the Pax 2 and the Pax 3. Comes in a 3pk.