A pedigreed purebred dog can be listed on either the Main Register (blue certificate) or Limited Register (orange certificate).
A dog on the Main Register (blue certificate) has full rights, meaning it is eligible for conformation showing, may be bred from to other Main Register dogs of the same breed and have their progeny registered as purebreds.
The Limited Register (orange certificate) is for dogs that are pedigreed but are ineligible to be shown at