Used to replace an outlet I had a fluorescent bulb plugged into so I could use a brighter LED garage light. To avoid punching knockout holes, I used a 4" round electrical box. As others have pointed out, you have to be careful with the exposed ground wire so it doesn't touch any of the terminals. I also found that the ones with The screws supplied with the mount were too short and I used the longer ones I had on hand Otherwise easy installation and operation as advertised.