Made from premium fir bark, Zilla Bark Blend is heat treated to efficiently absorb moisture maintaining humidity levels in the terrarium. This also eliminates the unwanted pests that are naturally found in bark creating a healthy environment for your reptile. Reptiles from a variety of habitats, from the tropics to northern forests, will thrive in additive-free Douglas Fir bark. Easy to use, great for your reptile friend, great for the environment. Produced in the USA with no additives, Zilla Bark Blend is completely biodegradable and can be composted after use, making it safe for pets and environmentally responsible. Packaging may vary as older bag designs are still in circulation.