Nickel Plated Steel is a wire used in quality musical strings. Because of the nature of the alloy, NPS has a little smoother outside feel. It also has a special kind of “Growl” that some people refer to. Full of tone and a great feel, Helix NPS is one of the great bass strings in the Helix Bass line. Helix NPS Bass features a patent pending design and construction. Just like the SS Helix Bass, NPS Bass features the Hyper Elliptical Windings (compressed from side to side), which gives Helix more Mass and Tone, as well as extended life. This Hyper Elliptical winding is what gives Helix its special feel—a more relaxed feel, with a lot less squeak and sliding noises than normal strings.
Give both Helix SS and NPS a try. It's the only way to find which alloy expresses your music the best. And like many other bassists, you may discover that having Helix SS on one bass and Helix NPS on another bass gives you the greatest variety of tones. This gives you the exact tone you want for any song!