The development of a new synthetic material that can imitate the acoustical characteristics of gut but without the typical defects such as high cost, short string life, and severe instability to changes of climate, has always been a fundamental goal of Aquila's research. Nylgut is the result. Nylgut's formula is protected by U.S. and International patents. Nylgut has a specific density and acoustical qualities nearly identical to that of gut, and is the first truly successful synthetic version of the natural product. Other strong points of Nylgut are its elevated resistance to wear under tension-greater than that of gut-but even more important is its extraordinary immunity to changes of climate, considerably better than that of Nylon and thereby ensuring a superior stability of tuning under normal conditions. Nylgut strings are quickly becoming the choice of ukulele players worldwide. Some say their instruments have been transformed by Nylgut strings. Nylgut strings for ukuleles are highly polished to a smooth surface.