Aprilaire 1610 Whole House Air Purifier, Easy-Install w/MERV 11 Filter - 16 x 25" Model 1610 is a whole home air cleaner designed for easy installation in upflow HVAC systems with right or left returns Built-in ductwork for applications that require a 90&deg; duct adapter eliminates the need for field forming transitions, significantly reducing installation time The return opening is adjustable, from 8" to 10" Cabinet includes metal tabs which can be used to secure the cabinet to the furnace or air handler during installation Recommended air flow is up to 2000 CFM Includes ME