If the stud/motor housing is in bad shape due to severe pitting or has been otherwise damaged beyond salvaging, feel free to hold it securely with whatever works, because they are still available as a spare part (and are included in a complete ringer assembly if you need/decide to replace the ringer).
家用摄像头网上专卖店满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满意意满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满满意意了我是我是我是我是我是我是我是非常满意！。