synthetic filter discs(filter disk): can be used within a pressure cooker, steam sterilizer or autoclave
synthetic filter discs (filter disk 90mm)are reusable, highly durable and have a filtration rate of 99.97% that means they will filter down to .3 microns.
synthetic filters discs fit precisely on any wide mouth 90mm canning jar which are commonly used by today's cultivators
12 Synthetic Filter Discs 90mm Superior to Tyvek filter discs "Wide Mouth" Size Used for Mushroom Cultivation
designed for 90mm wide mouth jar lids, you can also DIY them into regular mouth size or any other smaller sizes