This is a set of four white nylon strings for concert ukulele. These are nice high-quality strings that should work well on any concert ukulele or similarly-scaled instrument, including cigar box ukuleles! The intended tuning for these strings is that of a standard concert uke: high G, C, E A. These strings are about 22.5" in overall length and are not intended for use on instruments with a scale length of over 15".