Select Case not working

 Set GL = ActiveSheet.Range("d6:as6")
 Set SW = ActiveSheet.Range("aw6:cz6")
         
         If Process = "GL" Then
            GL.Activate
                        
            For Each Cell In Range("d6:as6")  '<--------- How do I call this properly?
                If Cell.Value = Designation Then
                    
                    Select Case Quantity.Value  '<----- Object Required
                    
                        Case 1 To 14
                            PostCol = Cells.Column
                            
                        Case 15 To 24
                            PostCol = Cells.Offset(0, 1).Column
                            
                        Case 24 To 999
                            PostCol = Cells.Offset(0, 2).Column
                      
                    End Select
                  End If
              Next Cell
          End If

This is part of a function I am trying to make. I am getting an "Object Required" error. Quantity is passed from the Sub to the function o.k. (Inteli-Sense shows the value for me). Can I not use a Select Case operation this way?

Also, when I start the loop, that is the only way I get it to recognize the range. How do I start that loop properly?

All help is appreciated!
Thanks!