Mirror gasket for 57 -59 Ford mirror.  The mirror should have M982 on base.  Some of the mirrors like this had the Ford Oval on the back of the mirror housing, and others had the oval on the mirror base.  This gasket should fit either style. The listing is for the plastic gasket only. The mirror is not included.  This is made of UV stabilized plastic, so it should hold up well.  You can see small machining marks on the outside edge of the gasket.  Still a nice replacement part that should work well and last a long time.