OIML weight are available in several classes. Stainless steel weighs. E2 weights offer superb accuracy for calibrating analytical and precision balances. F1 weights are suitable for calibrating precision balances. M1 weights are excellent for calibrating compact balances. Class : OIML Capacity : 10mg - 10kg Class : OIML E2 , F1 & M1 Stainless steel weights for durability and accuracy Plastic Container provdied Other weights is available