Use this Avantco LED light strip as a direct replacement for the ones that came standard with your Avantco WHAC-28 and BHAC-28 28" horizontal air curtain merchandiser. Each merchandiser uses two light strips, one at the top of the unit and one underneath the interior shelf. If your original LED light strips are broken or malfunctioning, replace them immediately to ensure your merchandiser is properly illuminating your chilled items.