An outlaw motorcycle club, commonly referred to as a biker gang, is a motorcycle subculture. It is generally centered on the use of cruiser motorcycles, particularly Harley-Davidsons and choppers, and a set of ideals that purport to celebrate freedom, nonconformity to mainstream culture, and loyalty to the biker group. The U.S. Department of Justice defines "outlaw motorcycle gangs" (OMG) as "organizations whose members use their motorcycle clubs as conduits for criminal enterprises".