Eternal Tungsten only carries tungsten carbide rings and wedding bands that use quality materials and presicion craftsmanship. Our rings are made with 85% tungsten carbide, which is the optimal percentage for maximum strength and durability. The rest of the 15% is nickel and some trace elements. Our rings do not contain any cobalt. Many people overlook craftsmanship. Not all rings are made the same. many manufacturers cut corners by not making their rings precisely. Therefore, you will find many rings on the market that are too thick and bulky, asymmetrical (the right side of the ring doesn't match the left side), and not the correct size. Our rings are made to be thinner and more comfortable to wear. One look and you will see our rings are symmetrical and our ring sizes are made to proper diameters for each size. All our rings are warrantied to be free of manufacturer's defects. All our rings come with a 30 day inspection period, so if you not happy with your purchase just return it for a refund. All our rings have a lifetime guarantee, which covers re-sizing and accidental damage. This means if you fingr size ever changes, simply send back your ring and we will exchange it for a new ring of a different size for the rest of your life. If your ring some how gets damaged, just send it back and we will replace it with a new one for the rest of your life.