Metallics JMSHC1230SS M12 x 30mm Metric Cap Head Hex Cap Screws - 18-8 Stainless - Each

The 30mm is the shank length under the head, so total material thickness plus nut engagement has to fit inside 30mm. On an M12 you want at least one diameter (about 12mm) of thread engagement in a tapped hole, which leaves roughly 18mm of clamped material. For thicker stacks, longer lengths in the same MSHC series are available by request.

18-8 stainless is the material here, which is the common austenitic stainless used for corrosion resistance in wet and outdoor service, so it holds up far better than a plain-finish carbon screw in a damp enclosure, strut channel, or rooftop mount. It is not the choice for chloride-heavy coastal or pool chemical exposure, where 316 is the usual step up.

They're built to ISO 4742 dimensions in the MSHC series. That matters if you're matching an existing fastener in a machine or panel built to metric ISO prints, since head diameter and socket size will interchange with any other ISO-dimensioned M12 socket cap screw.

It ships as a jar with a 100-count order minimum, so the buying unit is the jar rather than individual screws. Plan on that if you only need a handful for a single mount.

The JMSHC1230SS is flagged as both ARRA compliant and Buy American compliant in the manufacturer's data, with country of origin listed as China. If your specification requires domestic melt and manufacture rather than trade-agreement compliance, confirm which standard the spec is calling out before you submit it.

Grade is listed as 12.9 with a minimum tensile strength of 1220 N/mm2. That's the high-strength metric class, suitable where a joint is torqued to a published preload rather than just snugged, such as equipment mounting feet and structural brackets.