Again – buyers need to be aware that the directions and rivets are NOT included.
The rain rail is a plastic "rain gutter" (the cross section is shaped like the letter "U") that pop-rivets to the convertible top and every Miata has one. It is located at the base of the top below the window (you can't see it until you remove the top) and funnels the water that runs down between the top and the body of the car to drainage holes. If this piece is cracked or brittle, serious water damage can occur.