The gym gear urethane dumbbell set are made with a steel core coated in urethane these weigths are maintinance free and wont damage the floor if you drop them on it within reason these dumbbells have a smoother feel to them than rubber dumbbells these should last longer than any other dumbbells key features of the gym gear urethane dumbbell set strong and durable will last longer than any other dumbbells urethane coating making the dumbbells feel smoother and higher quality steel handle