The mark consists of a three-dimensional configuration of an electronic accessory for use with and mounting on an HVAC system in a home or business, being substantially rectangular in shape with right and left planar sides and a rounded top surface and a rounded bottom surface each having front rounded corners forming a front face having linear sides associated with the two planar sides and a curved top associated with the rounded top surface and a curved bottom associated with the rounded bottom surface and featuring two buttons, a first large circular convex button substantially centered on the front face and a second smaller circular convex button positioned in the center of the front face between the two sides and slightly below the first large circular button, and a rectangular display area positioned on an upper portion of the front face above the first large circular button, the rectangular display having rounded corners. The matter shown in broken line is not a part of the mark.