D'Addario EJ53T sets are designed for use with Hawaiian Tenor ukuleles. The 3rd string is a wound aluminum string complimented by a 1st, 2nd and 4th unwound string made from our warmest sounding black nylon. The original ukulele offering from D'Addario, each black nylon string is carefully center-less ground to an ultra-smooth, ultra-precise final diameter for excellent feel and unparalleled intonation with a warm, long lasting acoustic tone. This set is optimized for standard GCEA tuning.