Honeywell HE260A Higher Capacity Whole House Bypass Humidifier Bypass flow-through humidifier. Unit has air outing opening towards right. (The image on the retail packaging shows opening towards left but the actual unit has duct opening towards right) Enhance comfort and properly humidify homes up to 4,000 square feet Easy mounting on either warm air supply or return air duct of any forced-air furnace Flow-through design helps keep unit clean and decreases the frequency of maintenance Installation kit required. Sold separately.