Blacksmith AAOT Classical H; AA84H; Coated; String Set For Classical Guitar; Gauge: 28.7/44 Hard Tension Tension; Treble Strings material:Nylon, Bass Strings (Core): Nylon; Bass Strings Winding Material:Silverplated Copper; Winding Type:Round Wound; The Micro Carbon Shield coating, AAOT, prevents oxidation and dirt build-up on the wound strings and are designed to last even longer than the AOT strings. The perfect balance of consistency, tone, durability, and performance.