It makes tap water taste great! Binchotan active charcoal has been used in Japan as a water purifier since the 17th century. It may seem counterintuitive to purify your drinking water with a stick of charcoal, but binchotanan active carbon made from tree branches is renowned for its ability to soften water, add good minerals and absorb unwanted tastes and odors, such as chlorine. Use the charcoal with an Eau Good water bottle, which locks it in place so the filter won't knock around inside the bottle.What's it made of?Binchotan active charcoal filter (6 months life)How does it come?In a cardboard box, 19 x 6 x 2 cm approx.