Different guitars respond differently to different alloys. Some sound better with Bronze, some sound better with PhosBronze™. If you want a lot of power and punch, with lots of midrange and highs, or your guitar’s top needs extra punch to project, try a couple of different gauges to find just the right gauge for your guitar. PhosBronze™ is powerful and very bright while still having a smooth low end. PhosBronze™ comes factory equipped on many acoustics. 10-48 XL - 10, 14, 24, 30, 38, 48. 11-46 LT - 11, 14, 22, 30, 36, 46. 11-52 TLT - 11, 15, 24, 32, 42, 52. 12-54 CL - 12, 16, 25, 32, 42, 54. 12-54 ML - 12, 15, 25, 34, 44, 54. 13-56 TMD - 13, 17, 26, 36, 46, 56. 13-58 MED - 13, 17, 26, 38, 48, 58.