Sub CountUniqueChars()
Dim Col As Collection
Dim oRng As Range
Dim i As Integer
    If Len(Selection.Range) > 0 Then
        Set oRng = Selection.Range
        Set Col = New Collection
        On Error Resume Next
        For i = 1 To Len(oRng)
            Col.Add Mid(oRng.Text, i, 1), Mid(oRng.Text, i, 1)
        Next i
        MsgBox Col.Count
    Else
        MsgBox "Nothing selected"
    End If
lbl_Exit:
    Set Col = Nothing
    Exit Sub
End Sub