What metal are Argo floats made out of?

Argo floats are primarily made from high-strength plastics and are designed to withstand harsh ocean conditions. The internal components, such as the ballast weights and other structural elements, may include stainless steel or other corrosion-resistant metals to ensure durability and longevity in seawater. Overall, the materials used are chosen for their ability to endure the marine environment while minimizing weight and maximizing functionality.