The EJ65C is an all-nylon string set designed for use with concert ukuleles. Each string is manufactured on D Addario s own advanced monofilament extrusion line built exclusively for the production of musical instrument strings. This set is optimized for usage with standard GCEA tuning. Each set features their exclusive laser-sorted Pro-Art clear nylon trebles for unsurpassed intonation with a warm projecting acoustic tone.