The patented Nanoweb-Coating of the Elixir Strings prevents dirt and sweat deposits on the windings of the string. It preserves the sound even after repetitive playing. Elixir's Nanoweb-Coating does not affect the natural feel of the strings.
And that price is dullness. Compared to other strings, the low .135 is a bit flat, a bit dull. I bought a pair of them as backups for two different 5-string basses, and my experience is the same on both. This might be fine for plenty of styles of music, but unfortunately, it just turns to mud when playing metal or fast rock.