Car Audio Fitting Are There Car Audio Receivers That Fit Motorcycles? Or Do Motorcycles Typically Have Their Own Sized Units?

Are there car audio receivers that fit motorcycles? Or do Motorcycles typically have their own sized units? - car audio fitting

Try to see if I could buy a receiver car audio type default to a friend for their racing bikes. I think he can get a double-DIN format, is not it? A DINS fit?