Several years ago (perhaps 40 years) I had a mechanical pencil that had four finger-like grippers that held the lead in place. When the lead was extended, the grippers extended about a millimeter and opened to allow the lead to extend. When pressure was released, the grippers closed and returned to their normal position. I have attached a .png drawing to illustrate what I am trying to describe. Does anyone remember what brand made such mechanical pencils? I'd like to get another, but I cannot find any despite many Google searches.