is there anyway to change this code to not allow duplicate values in combobox

Set ws2 = Sheets("Sheet4")


Set rFind = ws2.Rows("1:1").Find(combobox1.Value, , xlValues, xlWhole)

If Not rFind Is Nothing Then
   comboBox2.Clear
    For Each c In ws2.Range(ws2.Cells(2, rFind.Column), ws2.Cells(150, rFind.Column))
   
        If Not Len(c) = 0 Then
            Me.combobox2.AddItem c
        End If
    Next c
End If

Thanks