OIML Class E1 – Highest accuracy class, primarily used as reference standards for calibrating other weights and reference standards. Due to their exceptional precision, these weights are used in environments where conditions like temperature, humidity, and pressure are carefully controlled. They must be handled with the utmost care to ensure their accuracy is preserved.
These weights are essential for research and development as well as precision calibration purposes, where even the smallest variation can affect results. Unlike other classes, Class E1 weights have no method of adjustment. This ensures their uncertainty is strictly controlled at 1/3 of the tolerance, guaranteeing unparalleled accuracy in highly controlled settings.
OIML Class E2 – Can be used as reference standards for calibrating other weights and are suitable for high-precision tasks. They are ideal for calibrating high-precision analytical balances with a readability range as low as 0.1 mg to 0.01 mg. Hence, making them essential for applications that demand strict accuracy and minimal measurement uncertainty.
E2 weights are commonly used in pharmaceutical, research, and laboratory environments, where accurate measurements are critical for quality control and experimental accuracy. Although slightly less accurate than E1 weights, E2 weights still require careful handling and controlled environmental conditions, including stable temperature, humidity, and pressure, to maintain their precision.
Laboratory weights are also called calibration weights or precision weights.
All Weights with E1, E2 accuracy class are listed in the link below
Cylindrical Knob Type Weights
Milligram weights