1-18 Dryer rollers
It would have a minimum of 4 and most had 5, 2 in the front and 2 or 3 in the back.
Another good thing to know about rebuilding 1-18 dryers is a MT dryer blower fits a 1-18 perfectly, and FD used the same type of cheap attachment of the blower to the motor that MT did, so if the blower shows any sign of coming loose replace it now while you are in there.
John L.