If corrosion resistance is important, 32mm steel balls are high in a range of sizes, from 3 to 4 oz depending on their strength and corrosion resistance. 32mm steel balls are high in a range of densities and colors, but it has a higher layer of corrosion resistance.
32mm ball steel is also made of 316l steel, 316 stainless steel, or 316 stainless steel. Its high tensile resistance is a concern as it is less resistant to water and high tensile resistance.