Loading Dock, Man Door, Business, Loud Bell Solution - Just add your choice of a n inexpensive door bell switch. We used this in a 10K warehouse to let us know folks or trucks were at the back door. Loud bell easily let us know in our up front offices, someone needed our help. Just mount the box - plug it in to any standard 3 prong AC (or 2 Prong with adapter just ask), as AC transformer is in the junction box. You only need an inexpensive door button switch (spst). Willing to help explain if there are any questions. Very straight forward and loud.