Royal flush brand mushroom grow bags. Heat-proof, autoclavable, pressure-cooker safe with micron filter patch. 10 mushroom grow bags of your choice. Choose from: 14a, 3t, 10a or 4a. 5 micron filter and holds 5 to 7lb of spawn or substrate. 2 micron filter and holds 5 to 7lb of spawn or substrate. 5micron filter and holds 3 to 5lb of spawn or substrate. 5 micron filter and holds 2 to 3lb of spawn or substrate. This item is made of polypropylene and nylon.