120u (microns)
120u refers to a 120-micron (µm) sieve, the mesh size used to sort trichomes when separating hash. The smaller the micron, the more selective the fraction.
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A glandular trichome head measures 40 to 110 microns in diameter: that is the range Punja, Sutton and Kim recorded on two high-THC cannabis genotypes (Journal of Cannabis Research, 2023). Filtration bags typically range from 220u, the work bag that holds back large plant fragments, down to 25u, the finest. A 120-micron mesh is therefore wider than loose heads: it lets them through and mostly holds back heads still on their stalks, clumps of resin and debris. Hash labelled 120u was collected on that mesh; a 73u-90u is a narrower fraction, made mostly of loose heads, a candidate for the full melt grade.
Stating a micron is a sign of seriousness: the producer is willing to say how the hash was sorted, and the figure can be checked against the observed texture. But the micron says nothing about potency: only the batch certificate establishes the dominant cannabinoid and compliance with the French 0.30% Δ⁹-THC threshold.
The stated characteristics and percentages of this product appear on its page. Without a dated batch certificate, its product profile is not a verifiable analysis.
73u, 90u, 120u: what each mesh holds
In a wash, the bags are stacked from widest to narrowest, and each bag keeps what passed through the mesh above without passing through its own. Placed under a 120u, the 90u therefore collects particles from 90 to 120 microns; placed under a 90u, the 73u collects those from 73 to 90. What these windows contain depends on the size of the trichome heads: 40 to 110 microns for the glandular heads measured by Punja, Sutton and Kim (Journal of Cannabis Research, 2023), 80 microns on average on industrial hemp and 129 on varieties bred for resin according to Small and Naraine (Genetic Resources and Crop Evolution, 2016).
| Mesh | What it collects | Typical result |
|---|---|---|
| 73u | Particles from 73 to 90 microns: mostly free medium-sized heads, with little debris | A narrow, light fraction, a candidate for full melt grade |
| 90u | Particles from 90 to 120 microns: the largest heads, mostly still free | Mostly whole heads; with the 73u, the window where the sought-after fractions are collected |
| 120u | Particles above 120 microns: few isolated heads on hemp with 80-micron heads, more on a large-headed variety; the rest is heads still on their stalks, resin clumps and debris | A less selective fraction, whose plant content shows in its colour and in the residue it leaves under heat |
Converting a mesh, comparing two fractions
The table follows the standard stack, but a label can state any mesh. The micron tool applies the same reasoning to the eight bags of the standard stack and turns each mesh into a size window. To see two meshes sold under the same name, the 45u and 120u ice-o-lator comparison sets three ice-water batches side by side: the finest mesh does not show the highest potency there.
Frequently asked questions
The size of the mesh that collected the fraction. A 90u keeps particles from 90 to 120 microns, mostly whole heads; a 120u keeps those above 120 microns, where heads still on their stalks and debris weigh more. The difference lies in the sorting; potency is read on the batch analysis, and choosing between the two is covered in 90u or 120u: which micron to choose.
No. The "u" stands for micron (µm), and 120u is the opening of the sieve mesh, 0.12 millimetre. The figure says nothing about a percentage or about CBD content: only the batch's certificate of analysis establishes the dominant cannabinoid and its level.
The mesh describes the sorting and says nothing about the plant the resin comes from. Cannabis resin is a narcotic under French law, listed by the order of 22 February 1990, whatever its mesh. A hemp resin from a variety listed in the EU or French catalogue is legal if its Δ⁹-THC does not exceed 0.30%, a ceiling the order of 30 December 2021 applies to hemp extracts and to the products that contain them.
The producer is announcing two neighbouring meshes combined, or the fraction collected between them. No standard governs this notation, so two different labels can describe the same batch: the observed texture, then the batch analysis, remain the two reference points.