D'Addario EJ88C sets are designed for use with all concert ukuleles. Each string within this set is made from our exclusive Nyltech material and optimized for standard GCEA tuning. Developed in cooperation with Aquila, D'Addario Nyltech strings are an exclusive combination of materials designed to deliver an optimal combination of warm, yet punchy tone, comfortable playability, precise intonation and tuning stability not found in other ukulele strings.