Easy - there is always room to innovate and improve. This allows the kettlebell to have a very clean seam, near perfect natural surface, and 100% balanced feel. Our cast iron kettlebells are traditional style, size, and weight. These natural surface kettlebells meet all of the specifications of the famous RKC and SFG bells. The natural surface is powder coated black and colour coded with rings on the handle. They provide a superior grip surface for any kettlebell enthusiast. The kettlebell is a cast iron weight (resembling a cannonball with a handle) used to perform ballistic exercises that combine cardiovascular, strength and flexibility training. By their nature, typical kettlebell exercises build strength and endurance, particularly in the lower back, legs, and shoulders, and increases grip strength.