Providing zoned comfort control in homes is now easier with our Full Line of Round Slip-In Dampers. Aprilaire now offers our round slip-in damper in 4 in, 5 in, 6 in, 7 in, 8 in and 10 in diameters. Virtually every home without zoning has comfort problems. It is now affordable to zone these homes without costly, and sometimes impossible, duct modification. By offering this simple solution, you provide your customers with true comfort throughout their home, better than operating constant fan or manually adjusting registers. You also assure your quality reputation with enhanced customer satisfaction through increased comfort and reliable, maintenance-free operation.