All Hatco Modular Heated Wells come with individual thermostatic controls for each well. A 1-, 2- or 3-well unit has a control box and bezel with 1, 2 or 3 thermostatic controls contained within it. The 4- or 5-well unit will have two control boxes with 2/2 or 2/3 thermostatic controls respectively. NOTE: Hatco offers adapter kits for units retrofitting failed APW and Wells units. These kits include a larger bezel that fits into the control opening left behind when the APW or Wells unit is removed, as the Hatco control box is much smaller than either of these competitive controls.