Warwick M4 EMP COATED Bass String Medium Warwick M4 EMP Coated Bass strings feature Enhanced Molecular Protection - a unique micron-thin coating that protects your bass strings against corrosion EMP Bass strings feel like an uncoated set of strings, yet last much longer Now you can have a long-lasting bass string with the tonal output and feel of an uncoated bass string One Micron That's all that stands between you and your bass' tone