... HIPS 2.Removable core,4 way air flow 3.Durable,adjustable 4.easy to install flow damper,ventilation dampers,louver vents damper ... -H-R, etc (For Reference)Main Software: AutoCAD, UG, CATIA, Solid works, etc Product Name flow damper,ventilation dampers,louver vents damper ... control the air volume.4. Removable core, four direction air flow , the windows are assembled with each frame, the windows can ...