The Chef Craft Eco Bamboo Fiber Mixing Bowl set is made out of 60-70% Bamboo fiber powder which is a renewable material. Bamboo grows 8 feet per day. The Bowls are also mostly biodegradable to help reduce the footprinting of landfills. This set contains multiple sizes for every mixing need: 0.25 qt, 0.5 qt, 1 qt, and 2 qt.