A true rocker is someone who lives a rocker's lifestyle. They themselves don't call themselves 'rockers', they have no need of defining themselves. Rock is all about sticking to what you believe in. Being what you want, not caring about whatever society thinks. This results to breaking the law/norms quite often.
Rockers mainly listen to any type of rock music.
There is no certain way rockers dress, but it tends to be in darker colors.
He doesn't care what others think, he's a true rocker.