A Sort of Coal product, Kuro cube purifies and refreshes the fridge naturally without the use of chemicals. It is made of powdered, compressed White Charcoal that is made by hand and is naturally activated during a controlled burning process. Activated charcoal reduces odors by absorbing gasses. It also produces a healthier environment and keeps food fresh longer. Kuro Cube can remain active for years by exposing it to sunlight occasionally so it can dry out thoroughly and thus regain its ability to absorb.