An improved scent pad and mechanism for housing the same. The mechanism is preferably a part of a humidifier or similar device and positioned adjacent to a heated surface. The mechanism preferably includes a cover, a keyed portion and a rib portion which allows the scent pad to fit properly and prevents other shaped pads from being inserted into or otherwise used in the housing mechanism, insuring optimal performance. In one embodiment the scent pad includes an upper straight edge, side edges, two lower beveled edges and a lower straight edge situated between the beveled edges. The upper straight edge and lower straight edge are preferably substantially parallel to each other. The side edges are preferably substantially parallel to each other and the beveled edges are preferably arranged at an angle that intersects both the lower straight edge and a side edge.