These washable, reusable thermal-bonded fiber filters are designed to work with your BoomRoom FAE Fan to keep unwanted spores and other contaminants out of your fruiting chamber. (Thermal bonding uses a heat process to bond fibers together without the use of acrylic resin, so they maintain their shape with no shrinkage when laundered.) Filters can be easily attached to 4" duct fan with clamps. To clean: Filters should be cleaned by hand with lukewarm water and sprayed with a 3% hydrogen peroxide solution.