All headlights have two chrome rings around them! The outer ring is just for show while this inner ring is the one that holds the light unit in place! While it is chrome, and thus does not rust too quickly, it still does happen. This 3 lug type which is about 18mm deep fits all headlamps that have a half metal inner bowl, such as original Lucas lamps. This is the budget type kept by most aftermarket suppliers. Sold singly and 2 required per car.  Also fits a Sprite , and MG Midget .