pl inform type of bus services available from hongkong airport to guangzhou - canton

I am afraid that I cannot grasp the meaning of "type of bus services"?
As far as I know, between the two places, several bus companies such as China Travel Tours Transportation, Eternal East Cross-Border Coach, Go Go Bus and Sinoway (HK-China) Express provide the cross border services and the buses are very comfortable.
In general, the bus ticket fare is around 200 to 250HK$ and takes about 4 hours on the way.