ELIXIR POLYWEB 80/20 ACOUSTIC GUITAR STRINGS. 12-56.12 56 E11075 POLYWEB CUSTOM LIGHT MEDIUM ACOUSTIC GUITAR STRINGS. Elixir Strings 80 20 Bronze Acoustic Guitar Strings with POLYWEB Coating, Light Medium (. 012 . 056) E11075 Acoustic guitar strings constructed with 80 20 (80% copper, 20% zinc) bronze wrap wire Played for a warm and robust tone that sounds "played in" but still retains a remarkably clear mid range