Countour 1100 Series Single Interior Switch - On/Off - Black. The Contour Interior Switch can be either surface or recess mounted. The interior series is supplied standard with a three terminal on/on switch which can be used for on/off circuits or two-way light installations. For applications such as shower drain pumps or electric toilets, momentary switches can be interchanged into the switch plate. Switches can be turned 90 degrees for horizontal mounting, and are current rated at 10A DC. All switches include a label sheet.