Product Type Venting For Gas Heaters, Compatible with Product Type Unit Heaters, Compatible Mfr. Model Number Low Profile Gas Fired Propeller Type Unit Heaters Sizes 030 to 075, Opening Width 4 in, Opening Depth 4 in, Mounting Type Surface, Vent Direction Horizontal or Vertical, Vent Diameter 4 in, Vent Size 4 in, Vent Type Intake/Vent Concentric Y, Material Steel, Outer Diameter 4 in, Includes Gasket, Inlet Collar, Sealant, Vent Box, Vent Cap, Wind Deflector, Standards ETL