AAMI Standard ST79 makes clear, utilizing paper/poly pouches to separate small items in a wrapped or filtered instrument tray is forbidden. This is because the poly laminate is a barrier to sterilization and being water repellent may contribute to wet pack. These paper bags are the ideal and appropriate alternative. They are made of 100% medical grade paper, which is porous to sterilant. Further, the moisture absorbent paper helps to dissipate condensate - helping to fight wet pack.