Made of 100% Natural Golden Bamboo. 100% Eco-Friendly, Bio-Degradable. No chemical used. Totally Handmade Product. Outer side polished with natural shellac for shining and waterproofing. Nothing used inside to keep natural condition. Useable Washable and Durable. If found fungus, please keep in sunlight for 2 – 3 hours and clean with dry cloth.