Brown Rice Flour Based Mushroom Substrate Fully Sterilized In Easy To Inoculate Half Pint Jars. Brf Jars Are The Perfect Growing Medium For Almost Any Gourmet Mushroom Strain. The Jars Are Filled With Nutritious Mushroom Substrate And Fully Sterilized For Your Convenience. Simply Inoculate Through The Flat Grey Self Healing Inoculation Point. Make A Circular Motion With Your Needle As You Are Inoculating To Evenly Distribute The Gourmet Mushroom Spore Solution. Brf Jars Also Have A Gas Exchange Filter So No Extra Layer Of Vermiculite Is Needed. Once Your Brf Jar Is Fully Colonized You Can Then Birth The Cake To Your Desired Fruiting Chamber. After You Have Birthed Your Cakes You Can Wash And Reuse The Jar And Lid As Well. Economic And Easy To Use For All Skill Levels Of Gourmet Mushroom Cultivation.