The weights are manufactured of the finest stainless steels available, including Troemner Alloy 8 Stainless Steel, which is available exclusively through Troemner. This unique material possesses closely controlled density (8.03 g/cm3), extremely low magnetic properties, good stability, and resistance to corrosion. Alloy 8 is the finest grade of stainless steel available and is similar to material originally specified in the manufacture of 1 kg state lab primary standards. Weights are designed so the specifications on surface finish,markings, construction, material density, and magnetic properties become more restrictive as the weight tolerances decrease in order to enable the weight to maintain its tolerance over time. These weights are designed for your most demanding weighing applications. Suggested Markets for Analytical Precision Weights include, but are not limited to, pharmaceutical, biotech, nanotechnology, life science, forensic and nuclear industries. ASTM Class 4 - For calibration of entry level balances and for student use. Surfaces are polished to a perfect, mirror like finish. Masses are less vulnerable to wear and scratches. Low magnetic susceptibility, uniform consistency and high resistance to corrosion. 1mg to 500mg weights are one-piece construction with no adjusting cavity and turned up end for easy handling. 1g to 5kg weights are two-piece construction with adjusting cavity and handling knob.