This is our most popular product that saves the grower lots of time preparing substrate. Our Sterilized grain spawn is guaranteed 100% sterile. We have tried and tested hundreds of methods of sterilization and have the finest machinery possible from overseas to be able to produce these at such high quality. Our bags are composed of Sterilized grain in a specific grain recipe mix that we have discovered after years of trials. These Bags come in 2 pound unit sizes which are perfect ratio to use 3 bags per large mono tub. The bags come with Pre-installed 0.2 micron hydrophobic filter and a Pre-installed self-healing injection port.