Augustine Acoustic strings began when Danish immigrant Albert Augustine collaborated with the famed guitarist, Andres Segovia, to develop the first nylon, Guitar strings in the 1940S. Augustine has developed acoustic and electric guitar strings with the same renowned superior sound and quality. The acoustic strings are constructed of a phosphor bronze wrap over a hexagonal core. Choose from ultra-light gauge (.010-.047), extra-light (.011-.052), light (.012-.053) and medium (.013-.056). The extra light set features: · E1 - .010 inch. - 0.25mm · B2 - .014 inch. - 0.36mm · G3 - .023 inch. - 0.58mm · D4 - .030 inch. - 0.76mm · A5 - .039 inch. - 0.99mm · E6 - .047 inch. - 1.19mm.