Mirror or camera on Rossi's bike?

Last few races I've seen a 'mirror' showing the reflection of the rider behind Rossi. How do they do that? I don't see it when they show the bike in the pits

Last few races I've seen a 'mirror' showing the reflection of the rider behind Rossi. How do they do that? I don't see it when they show the bike in the pits http://ifttt.com/images/no_image_card.png