Which is the best brush that I can use to paint the sealing of a bathroom with oil paint?

a Purdy brushWhich is the best brush that I can use to paint the sealing of a bathroom with oil paint?
if your painting the whole ceiling use a roller it is much faster 3/4 nap and you can throw it away when your doneWhich is the best brush that I can use to paint the sealing of a bathroom with oil paint?
when using oil paint always us a natural bristle brush NOT NYLON