The inner material of the rubber-coated dumbbell is cast iron or pure steel, and the outer part is wrapped with rubber material. This design makes the rubber-coated dumbbell have comfortable feel and anti-slip function, and the rubber outer layer can also provide protection, which is not easy to rust and prolong its service life. The quality and material of encapsulated dumbbells will vary from brand to manufacturer. When buying rubber-coated dumbbells, we need to choose famous brands and reliable sales channels to ensure the quality and safety of the products.