Kishu Charcoal - X-large Activated Charcoal Water Filter for 3-5 Gallon Jugs Kishu Charcoal X-Large for 3-5 gallon jugs used to purify large quantities of water. One sticks lasts 4 months - then use as an odor absorber or break it up for use in the garden. Kishu is easy to use - simply place in a large jug of water add tap water and allow Kishu go to work bonding with toxins.