These charcoal sticks are harmful to your health. I tried them to purify city water and got very sick. The sticks are sent without any information about what pollutants they claim to remove from the water. There is also no indication of what type of water they can be used in. City water, for example, contains all sorts of contaminants such as raw sewage, heavy metals, pharmaceuticals, herbicides, pesticides, etc. This company needs to stop playing with their health and the health of our pets.