Hypodermic Stainless Steel Tubing - Medical Needle Fabrication | Vita Needle Company Vita Needle offers stainless steel wire in several medical grades and tempers. Typically sold in hard temper, SS 304 wire is our most common alloy. Chemically, SS 304 and SS 302 wire are very similar, except for a higher carbon content in 302, which effectively gives it a higher tensile strength for a given amount of cold work.