Make safe drinking water on your rocket stove! We have added a pasteurization indicator (WAPI) to our pasteurizer. Remove water cap/knob assembly and inspect pasteurization indicator tube to verify the red wax has liquefied and dropped to bottom of pasteurization indicator tube. This indicates water has reached pasteurization temperature and is now safe to drink! Turn pasteurization assembly upside down on flat top and indicator wax will return to top of tube and solidify for next use. Water pasteurization is a heat process used to kill harmful bacteria and make water safe to drink for human consumption. Heating water to 65º C (149º F) will kill all germs, viruses, and parasites. Pasteurization can be accomplished without having to bring the water to a boil. Paired with a StoveTec Rocket Stove, approximately 4 liters of water can be brought up to 65°C (149º F), the temperature required to pasteurize water in mere minutes. There is no water filtration system included with this product. Heavy metal contamination or toxins are not affected by pasteurization. Pasteurization will not help if water is brackish or chemically contaminated.