Diameter: 15cm/5.9inches; 11cm/ 4.3 inches Pre-filter, activated carbon filter and true filter tree layers design cleans air This 3-stage High-Efficient Filtration System Replacement Filter effectively removes 99. 97% of airborne particles as small as 0. 3 microns to provide you and High-strength and environmental protection material, designed to meet the quality, rigorously tested for compatibility and service lifetime. Please remove the of filter from before placing