Its other resonator instruments include a 12-string guitar, ukuleles and mandolins. National also produced resonator ukuleles and resonator mandolins. Johnson has also produced resonator ukuleles and mandolins. Apart from guitars, the company currently produces acoustic basses, mandolins and ukuleles. It is a common tool for players of guitars, mandolins, mandolas, banjos, ukuleles and bouzoukis. Breedlove produces acoustic guitars, acoustic bass guitars, and ukuleles. Elderly's repair department services other fretted instruments such as banjos, ukuleles, and balalaikas. They made many types of string instruments, including ukuleles, acoustic and electric guitars and violins. Common types of ukuleles include soprano (standard ukulele), concert, tenor, and baritone. Products manufactured by Cort include electric, acoustic and classical guitars, basses and ukuleles. Like standard ukuleles, banjo ukuleles were originally outfitted with gut strings. Different musical instruments, such as lutes, ukuleles, flutes, and others can be used to play. This makes Koa ukuleles very distinguishable by sound. Bamboo has also recently been used for the manufacture of guitars and ukuleles. Not only are koa ukuleles distinguishable by sound, but also by looks.