Inner layer is made of Quality Iron and outer layer from Vinyl Coating (Non slip layer). High quality Vinyl Coats prevent them from damaging your floor or tables provides durability. Comfortable grip. High quality GYM DEPOT kettlebells help to improve body Strength and shape body muscles. Can be used like ordinary dumbbells and swung about for an intense cardio workout. Helps you have workout in very little space and you can burn up just as many calories, as going for a run. You can do a large number of exercises with a kettlebell like cardio vascular and anabolic exrecises at one time.