Large Kishu Binchotan Charcoal Water Purifying Stick, Filters 1-2 Gallons of WaterJapanese binchotan charcoal from Kishu, Japan is the highest grade Absorbs impurities from water, resulting in pure, great tasting water (filtering time for 1 2 gallons of water is 6 7 hours) Use 1 stick for 1 2 gallons of water; stick is approximately 2. 5 3cm in diameter and 15cm in length Reactivate charcoal every two weeks by boiling for 10 minutes and letting dry Material: binchotan (Japanese Oak) charcoal from Kishu, Japan