Replacement rollers for sliding screen door

To tell the truth, my wife likes the 84-008 nylon wheel. She says it makes less noise on the screen doors at home. I personally like the 84-008M because I believe it lasts longer, since it's metal. It is really a matter of preference. I usually install the 84-008M on the bottom and the nylon version at the top, while lubricating the wheels and tracks from time to time. As for the patio door corners, they are what hold the patio screen together at the ends.