Abstract: A wall switch and a wall outlet each comprises a plug-in unit to be inserted in a niche installed on a base which also includes a panel and a base plate bing fixed together. Between the panel and the base plate, a control frame and a movable latch are sandwiched, and each of them has a projected end extending out of the apertures in the panel so as to facilitate manual operation for removing the plug-in unit. In addition, a thumbtack pin may be furnished at the back of the base plate, penetrating through the base plate and the movable latch so as to prevent the plug-in unit from being removed directly.