These weights are of highest metrological accuracy class and used as primary reference standards for calibrating other lower class reference weights like E and blow classes , E class weights are integral /single piece monobloc type weights , E class weights have no method of adjustment. These weights are appropriate for calibrating high precision analytical balances with readability as low as 0.1 mg to 0.001 mg. The Masseprazise High-Precision E Class Calibration Weight is a premier reference standard designed for use in the most demanding measurement environments. Engineered with the highest metrological accuracy, these calibration weights serve as the foundation for calibrating lower class reference weights such as E and blow class weights, ensuring superior precision in analytical measurements.