Exo Terra reptile bark is substrates in natural terrariums have many function and is not only there for decoration purposes. Play an important role in the determination of the terrarium"s microclimate. The Exo Terra reptile bark substrate is 100-percent natural fir bark. It readily absorbs and releases moisture and is perfect for humidity loving reptiles. The substrate helps control air humidity levels and stimulates natural digging and burrowing behavior. This product weight is 3.94-pound. Available in 8-quarts.