... Chinese sports equipment manufacturer speclizing in manufacturing sports and fitness equipments ,etc. rubber dumbbell 1.material:rubber ... 1, raw materials: the main material is cast iron, and some outsourcing is a layer of rubber. 2. ... specification: the middle is the iron bar, both ends of the solid ball, because ... 10,15,20,25,30 kg and so on. , ranging from circular iron plates, about 40 ~ 45 cm ...