This 2-Pack features high-density polypropylene durability and resilience. Includes 8 Monotub Filter Disks, 2 liners and 8 Plugs. Air Exchange - It has 4 air holes with our 2.5" Monotub Filter Disks strategically placed to give mushrooms the best growth environment. Small but Mighty! 28 Quart volume measuring 12" x 12" x 12" OD, this chamber offers plenty of space while keeping the size compact. Incubation Control:With the provided hole plugs, easily manage airflow during the incubation phase, guaranteeing optimal growth conditions. Stackable & Sturdy:Designed with a stackable base that can support up to 10 bins stacked atop one another. Each monotub can support 150 lbs Ideal Quantity of Grain to use per tub:32-48oz (1.0-1.5lbs) | Bulk Substrate:4-5lbs Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.