An excellent choice for warm air heating systems. Designed to fit today's narrower plenums - as narrow as 10” (HFT2100) or 14” (HFT2700). Reversible side panels with unique snap-lock fittings permit easy-change left-side or right-side bypass installation. New, improved wicking and water distribution system allows for non-level plenums. Durable thermoplastic cabinet resists rust, corrosion and warpage.