250r Chain Rollers. What size do I need?

[atcmatt]

Hi guys, the two chain rollers on the top and bottom, plastic things with bearings. I need two new ones for my R. How do I know what size I need or is it a standard thing? Also, best place to snatch them up?

On another topic, where is my best plase to get a new tank, shrouds and front fender for my bike? That will ship to aussie?

Thanks.

Matt