For owners of the Artograph 2025 Spray Booths. Artograph 2025 Filter Pak contains 4 each mid-filter and poly carb filter pads. The mid-filter is a non-woven air-laid polyester substrate with a green PVC binder on the exit side. The poly-carb filter is a carbon-impregnated polyester offering high odor and further particle-trapping efficiency. Every three months with regular use, replace both filters at the same time or when replacing the Pre-Filter Roll.