The Cold Air Return by Vogelzang is designed to work with any Vogelzang Add-On Furnace. It covers the blowers and connects to the existing HVAC return duct work, or newly installed ducting. And the CR-25 had a place for a 16 in. x 20 in. air filters for cleaner air. Designed to last for years and provide trouble free service, this attachment is a great investment for any furnace.