Barbershop arranging is the art of creating arrangements of barbershop music. The Barbershop Harmony Society (BHS) and Sweet Adelines International (SAI) have prescribed rules that dictate what is an acceptable arrangement, particularly with regard to singing in competition. This makes barbershop arranging a specialist form of arranging, rarely tackled by those outside Barbershop; likewise, barbershop arrangers tend to be known only for their barbershop arrangements rather than for their work in any other musical form