UltraClass calibration weights are designed to handle the most demanding calibration needs while having the ability to be adjusted. Consistent automated measurement means that UltraClass weights are the most precise two-piece weights available with weight tolerances that equal or exceed comparable ANSI/ASTM E617 and OIML R 111 class tolerances. All the UltraClass calibration weights, 1 gram through 20 kg, are made exclusively out of stainless steel. At Scales Plus, we carry a wide selection of all calibration weights. For more questions about calibration weights and what kind would be best for you application, please contact us. You can reach us through the livechat, via email at firstname.lastname@example.org, or by calling 616-622-2100.