Warwick M5B EMP Coated 5-String Bass Strings feature Enhanced Molecular Protection - a unique micron-thin coating that protects your bass strings against corrosion. EMP Bass strings feel like uncoated strings, yet last much longer. Now you can have long-lasting bass strings with the tonal output and feel of uncoated bass strings. One Micron. That's all that stands between you and long-lasting bass tone.