GREOAK green rubber air purifier for nano crystals and activated carbon filter Specifications: 212x386x13 mm Features: 1, pure diatom will turn yellow, in addition to the effect of formaldehyde is several times this single points; (2) adsorption of nanoporous potent toxic harmful gases such as formaldehyde, TVOC, benzene, ammonia, odor; 3, through sun exposure, recycling, and no secondary pollution.