Fuertemente influenciados por bandas como Green Day, Blink 182, o Bad Religión, tratan de elaborar su propia versión en español del contundente sonido "west coast" americano. El grupo esta formado por Fefe (voz, guitarra), Ivan (bateria), Sergio (coros, teclado), Mike (bajo, coros) y Fito (guitarra, coros).
Callahan is a band formed in Guadalajara, with musicians of anothers bands of the region. Strongly influenced by people like Green Day, Blink-182, Bad Religion, they do their own version of the convincing american west coast sound. The members of the band are: Fefe (vocals and guitar), Sergio (chorous, keyboards), Ivan (drums), Mike (bass, chorous) and Fito (guitar, chorous).