Solid and Durable Cast Iron Weights Cast iron grip handle weights are manufactured in accordance with International Recommendation OIML R111 regarding material, surface roughness, density and magnetism. The two-component coating ensures a smooth surface free of cracks, pits and sharp edges. Each weight has an adjusting cavity located on top of the weight. The new color code avoids mixing up of weight classes. Weights are available in OIML classes M1, M2 and M3 with nominal values of 5 kg, 10 kg, 20 kg, and 50 kg.