I strongly suggest every bag owner to check their bags because the size of the openings on the sieves can be way different than the seller claims. This means you might be flushing your hash down the drain, smoking leafy hash or simply a different quality you might wanted to smoke. When I used my bags for the first time I left the water in a bucked after the procedure. I noticed that there was still a lot of residues collected on the bottom of the bucket even after it was screened with the 25 micron bag. So I checked the bags with a cheap microscope and compared the size of the openings on the sieves with a millimeter scale. I noticed it was way off so bought a stage micrometer and measured the holes on the screens. 4 bags costs more than 100$ so I wouldn't say it's cheap. The seller told me it must be the the manufacturer's fault, and sent a new set of bags from the new batch a couple month later, but these were still off the scale. 2 sets of bags + pressing screen + some sieves straight from the manufacturer. Stage micrometer: 25um bag is 86um in reality: 25um bag is 70um (from the new batch): 25um pressing screen is 74.5um 75um bag is 81um 75um bag is 89um (new batch) 110um bag is 132um 220um bag is 174um 220um bag is 313um This sieve is from an other source, it's being sold for printing. I bought it as a 31 micron sieve, and it's also written on the screen itself so there is no doubt about that. This means the measuring method works and exact. First I used a millimeter scale printed on paper so the measurements are not precise, but the scales are visually comparable, so you can see what happens to a sativa or indica gland. Residue at the bottom of the bucket after the "25" micron sieve and some settling and siphoning: Leafy shit: So anyone who has a 80 micron bag instead of 25 micron might be pouring the best quality hash down the drain while his hash is made up mostly from powdered leaves. I used ImageJ (opensource freeware) to process the images and make the measurements: ImageJ Anyone can check the bags with a cheap microscope or with a decent camera, some microscopes with a known field of view can be used without buying a stage micrometer (costs couple of dollars) Measuring the usual way: http://www.ruf.rice.edu/~bioslabs/methods/microscopy/measuring.html These bags are still sold on the web, the seller told me he sells 1 set per day. I won't say what brand is this, so everyone will have to check his own. Either way these bags could be sold under an other name, so it's better to check your own.