We use this after strong or weak notrumps. Once the penalty redouble is exposed, we are in a force at the 2-level only.
Immediate doubles are penalty at any level.
4333 hands are sometimes shown this way. In general, redoubles are takeout except after the business pass. Responder is not expected to correct. We will psych responses even after a double if we have a good place to run. If opener chooses a suit and responder overrides into a different suit, that suggests a psych.