Thomastik Jazz Bebop BB113 jazz strings 13-53. Probably the only round wound guitar string that can truly be called a jazz string. A similarity to the JAZZ SWING in materials and string architecture, but with a small gauge round wound nickel winding, produces a strong, fundamental rich jazzy tone that is somewhat brighter than a flatwound. This remarkable string is an excellent alternate choice or the player wanting real jazz tone, but with a bit more of an "edge".