These premium autoclavable mushroom grow bags are 3 millimeter polypropylene with 0.2 micron filters and self-healing injection ports. They work great for producing spawn and fruiting blocks weighing 5-7 lb per bag/block. You don't need a fancy laminar flow hood or still air box to inoculate your mushroom blocks at home. Simply inject directly through the built in self-healing injection port with your favorite liquid mushroom culture. These bags are Unicorn brand, 3T bag type. The dimensions are 8''x 5''x 19''.