Rice Lake 12503 Stainless Steel Cylindrical Metric Individual Test Weight, 5g Mass, NIST Class F Metric, cylindrical, type-II weight with sealing cavity for adjusting overall weight Stainless steel construction for stability, resistance to corrosion, and low magnetic susceptibility Meets National Institute of Standards and Technology (NIST) Class F specification for commercial "Legal-for-Trade" weighing operations Weights 100g and over have a sealing cavity for adjusting total weight