Like other instruments in the violin family the viola has a long history - of the four common orchestral strings it is the second oldest after the violin. Violas are similar to violins in appearance but are larger and are tuned one perfect fifth lower which is in turn an octave above the cello. For all its similarities the viola does exhibit several unusual traits compared to its siblings: most uniquely that music for the viola is usually written in the rarely-used alto clef (although some higher-register compositions may use the treble clef instead). Much of modern viola repertoire was written in the 20th century but the instrument is capable of playing many violin parts that date back far earlier.
Violas are often packaged in "outfits" which include critical accessories such as a bow and case as well as the instrument's strings bridge and tuning pegs pre-installed. Most major manufacturers offer their violas in this way including Bellafina Maple Leaf Strings Otto and Strobel. Certain brands specialize in unique varieties of the viola in which case the accessories required for that model are generally included - NS Design for instance is an electric instrument maker and their electric violas are packaged with special chinrests designed to fit their unconventional shape.