Various wires and methods of making the same are disclosed. In one aspect, a wire is provided that includes a core and a tube around the core. The tube is composed of an alloy containing about 33 to 37% nickel, about 31.5 to 39% cobalt, about 9 to 10.5% molybdenum, and about 19 to 21% chromium. The wire has an ultimate tensile strength of about 150 to 250 kpsi, an amount of cold work following a final anneal and a torsional ductility of greater than about 6 turns-to-failure per inch of the wire.