This bag includes an injection port as well as filter.  It is often used in the production of grain spawn and holds up to a kilogram of spawn.

This side-gusseted breathable bag gives a sturdy stand-up bag after filling and a strong bottom seal. Manufactured with custom-designed equipment and proprietary additives, Unicorn Bags are pliable at any temperature as well as after sterilization. The bag opening is designed for easy sealing and the bag’s bottom seal can withstand agitation.