AquaRain 4-Pack of Ceramic Elements Laboratory Proven Safe Drinking Water processed from Wells, Rivers, Lakes, Cisterns Patented Sub-Micron Ceramic Technology coupled with Silver Impregnated GAC Gravity Powered Energy-Free Process, NO electricity, NO plumbing, just pour water in! Lasts for 1000's of gallons, convenient everyday use, and perfect for emergency situations Includes 4 each Replacement Sub-Micron AquaRain Ceramic Elements