This bag contains 4.5 lbs of hardwood sawdust mixed with soy hulls. Perfect moisture level. Come already sterilized and ready to go. You can use this substrate to grow any variety of wood loving mushrooms, including shiitake, oyster mushrooms, lion's mane, maitake, pioppino, turkey tail, enoki, and many more. The bags do not have injection ports. These are not good to grow any "specialty types" of mushrooms. Please note: spawn and/or spores are not included.