Other advantage of mycelium based composites is that this substance acts as an insulator, is fireproof, nontoxic, water resistance, rapidly growing, and has an ability to bond with neighboring mycelium products.[45] Mycelium based foams (MBFs) and sandwich components are two common type of the composites.[3] MBFs are the most efficient type because of their low density property, high quality, and sustainability.[5] The density of MBFs can be decreased by using substrates that are smaller than 2mm in diameter.[40] These composites have higher thermal conductivity as well.[40]