PROIRON neoprene coated dumbbells are made from compact solid cast iron covered with thick textured neoprene, The high-quality neoprene coating is odourless and makes holding the dumbbell easier even with sweaty hands and protects floors from damage, it is also easy to clean. The design of the dumbbell also means they do not roll. The materials used are strictly selected and certified, free of phthalate and lead, so they are healthy and safe to use for your daily exercise. If you want to get in shape with simple and effective home exercises, this set of dumbbells is a great starting place, included is a FREE fitness guide to help you choose effective exercises!