Rotosound Ultramag Electric Guitar Strings (9-42) - Nickel Iron AlloyULTRAMAG from Rotosound! Made from a special "Type 52" alloy with increased magnetic and corrosion resistant properties Rotosound is proud to present Ultramag! Rotosound's materials expert John Doughty explains Ultramag: "With a composition of 52% nickel and 48% iron, this highly magnetic string will certainly accentuate those middles and lows over their steel counterparts. Designed for use in the aerospace industry and high end electronics, the low