Zonon 256 Pieces Synthetic Filter Paper Stickers 20 mm 0.3 ?m Synthetic Filter Disc Tape Mushroom Applied Under Wide Mouth Mason Jar for Mushroom Cultivation

So handy! Easy to use! Way better than tape or poly-fil! Will definitely buy again!

Great product does what it is supposed to do

They work great 👍🏻

I love these filters I use them in my PC they are waterproof) . They allow air in and keep impurities out. They stick to my metal covers Welland there's a bunch in one order. Great value good quality and the same one can be used a couple of times

I have used AND REUSED these filters on well over a 1000 different jars of spawn. From WBS, to Corn, to Oats I have had and maintained tremendous success using them. Any contam’s I can only equate to my own doing. Because like I said I’ve used & reused these filters multiple times w/ no issues. If your spawn has somehow been contaminated. I would definitely change it out before the next use.I would recommend using plastic lids since they won’t rust from multiple uses. I also recommend using a 1/4” drill bit for your Gas Exchange (GE) hole. As this seems to be the perfect size and best fit for these filters!I HAVE ONLY EVER NEEDED TO PUT 1-FILTER ON EACH JAR! Ive seen ppl say to use multiple but IMO I do not feel it’s necessary. I place on top on the outside of every jar. That goes for both regular & wide mouth lids.

I put these on mason jars for mycology projects. Used to get contamination all the time before I started using these. Now I can't live without these

Exactly what you'd expect. Works great.

These are perfect and Ive used them successfully for some time now with no contamination. Thank you for offering these at a fair price!