Highly polished kilogram and gram weights made of Troemner Alloy 8, which is a specially developed austenitic stainless steel that possesses closely controlled density, extremely low magnetic permeability, good stability, and resistance to corrosion and handling damage

Fractional weights 500 mg to 5 mg are made of stainless steel (30 mg weights are aluminum); fractional weights 3 mg and below are made of aluminum.

This exclusive material has a density of 8.0 at 25 °C (controlled to ±0.1%), is essentially nonmagnetic in the annealed condition, and will not transform to magnetic under any combination of temperature and cold work down to –195.5 °C (–320 °F).