These are 50x autoclavable Unicorn 10A mushroom grow bags. They are commonly used for making mushroom spawn, they have a finer/smaller pored filter for less chance of contamination. 
 
Type: Gussetted
Material: 3.0 Mil Polypropylene
Bag Size: 5″ X 4 X 18″
Filter Type: A
Filter Size: 1.5″X1.5″
Filter Pore Size: 0.5 microns
Filter Hole: Style L
 
This side-gusseted breathable bag gives a sturdy stand-up bag after filling and a strong bottom seal. We manufacture it with equipment we designed and with 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.