A flexible, strong, yet micro-thin polymer tube defends the critical tone zone from invading enemies. Nothing ( including the coating ) gets between the windings. Elixir strings with the original Nanoweb coating applied, sound great, last 3 to 5 times longer than ordinary strings, have the bright tone & punch of non-coated strings & feel like traditional strings. After experiencing Elixir guitar strings, it's hard to go back to the old way of life. Gauge 12450 - 10 / 10 / 13 / 13 / 17 / 09 / 26w / 12 / 36w / 18 / 46w / 26w.