12 Synthetic Filter Discs 90mm for a Buchner Funnel and Cut Them fit"Wide Mouth" Size Used for Mushroom Cultivation

Excellent, despite being slightly larger than a large mouth lid.

Using these one can put jars atop one another saving shelf space, and they breathe well even if I screw lids on very tightly, though that is completely unnecessary. I boil jars, lids, and filters a day before filling and pressure cooking and store them in the laminar flow hood till the next day, and have far less contamination than any other type of filter, such as those stick on patches or those filters one sticks into holes in the lid. In fact, I've used these hundreds of times and never found contamination at all with these. Spores won't fall upward under the lid and make it to this filter, whereas gravity eventually carries spores through or onto damp 2 micron patches if they are atop lids stuck in grommets or glued on. Once spores land on the top surface of a damp filter, the other type that is, they will sprout and grow right through it much the same as the way mushrooms or molds will grow right through filter patches on grow bags requiring a clean hepa filtered room for those to be used. Place the smooth 2 micron side of the filter toward the stuff inside the jar and the fibrous side toward the inside of the lid. They should tell you that but I think they expect you to know already. Also, I boil these and reuse them over and over again without problems, and have no troubles from the water still making them wet while in use. They are three or four millimeters wider than the inside of the lid, so centered carefully in there they hang over past the edge of the jar's glass perfectly, and growing jars of substrate can be stored on a shelf in a room not hepa filtered.

So, I had to buy some of these filters to answer my own questions:1) The 90mm size is slightly too big to fit inside a white plastic wide-mouth lid. It is easily trimmed with scissors but you should buy the 87mm one.B) Compared to the Fungi Perfecti filters, these are the same thickness but softer, and only one side feels smooth and sintered. The other side is fuzzy like felt. They will absolutely perform the same task, but may not enjoy repeated washings the same way.

I bought these to cover 1/4 inch holes drilled in plastic wide-mouth jars lids.I'm doing the tek that only requires a penny-sized circle to cover the hole and usse heat to melt the plastic lid around the hole and stick the penny sized circle ontop.Each disk got me about 12 penny-sized circles... meaning that 12 disks will give roughly 140 penny sized circles.

I drill a half inch hole in the mason jar lid and then put the filter on in place before sealing up the jar before pressure cooker sterilization of the rye berries. This allows the developing mycelium fresh air exchange with no risk for contamination. Good Luck!

Wow. This is so effective and easy to use and reuse. Allows gas exchange and keeps contamination out. I modify these for my needs. I use a paper punch and punch out a hole in the center. Fill the hole with red RTV high temperature gasket sealer to make a self sealing port. Wax paper does not stick as it is drying. Pressure can to sterilize my mushroom mycelium solution only 15 mins max at 15 pounds pressure or it will scorch the sugar and it won’t grow mycelium . Let it cool. Then wipe the port with alcohol and use a syringe to inject into the port. You can also cut them down. Hold a small mouth jar lid against the soft side and it won’t slip when you use scissors to cut around the lid. The picture is what 2cc of a 10cc syringe of mycelium injected into sterilized solution looks like in about 2 weeks. The growth is much increased with the air exchange. Using it on a pasta sauce jar. 1 1/2 Tbl spoon of corn syrup and 1/2 Tbl molasses in 1/2 gallon water is what I use. Also use to make reusable agar culture jars.

This isn't my first SFD rodeo, have been buying them as needed for many years now and the quality and construction of these was not what I was expecting compared to any synthetic filter disc that I have purchased from previously. these are seemingly have a completely different material, softer, more bendy/pliable, seem to have less integrity and form overall. Previous synthetic filter discs (sfd) have always felt kind of foamy, almost like a thick paper coated in foam (although I am aware they are not made of paper, they are completely synthetic) I don't know how to describe the feel of other than that they're more like fabric or felt I guess, one side is shiny, the reverse is knit material that will catch on your hands if they're a tiny bit dry. Thickness is about the same. I have included photos so you can observe the differences for yourself. Please ignore the pink and other colors that you see along the outside of the older style sfd, I was using it as a template for tracing on these new ones that I'm reviewing, the new ones do not fit in the grey plastic ball leak proof lids and must be cut down

So far good. Attached to lids and Pressure cooked them and they still work great. Happy customer and not a waste of money. They serve there purpose well.