Soft Flex® Wire is brought to you by state of the art, micro-wire technology. Soft Flex® Wire is constructed of either 21 or 49 micro woven, stainless steel wires, braided together and then nylon coated. This micro-wire technology gives you the most flexible and knittable stainless steel in the world. It is hypoallergenic, and since Soft Flex® Wire is marine quality, it can be worn in and out of salt and fresh water. Each diameter was designed to handle certain level of abrasion, everything from soft materials like pearls and seed beads to rougher materials like glass, minerals and metal. The purpose of this product is to eliminate the frustrating task of re-stringing your designs due to cutting and breakage. We recommend you consider the abrasion level of the beads you are stringing in order to determine the appropriate diameter of Soft Flex® Wire you will need. The thicker the wire, the better resistance to breakage it will have.