GRIP in cast iron grip covered in polyurethane (PU). Polyurethane is the best material to produce records. The particular design of the discs always guarantees an excellent socket and ease of use: both with our balances and alone, for example during the lunges or in the exercises for the core. The steel ring guarantees easy insertion in all our barbells and high resistance to self -resistance. The closest thickness than the Bumper will allow you to load our barbell more. The discs will occupy less space on the sleeves giving a feeling of greater compactness and solidity to your workout.