Private Sub Workbook_Open()
    ThisWorkbook.Workbook_SheetActivate ActiveSheet
End Sub

Public Sub Workbook_SheetActivate(ByVal Sh As Object)
    If Sh.Name = "Base" Then
        With Application.CommandBars("Cell").Controls.Add(Type:=msoControlButton, Temporary:=True)
            .Caption = "Send"
            .OnAction = "Send2Spec"
            .FaceId = 1154
            .BeginGroup = True
        End With
    ElseIf Sh.Name = "Spec" Then
        With Application.CommandBars("Cell").Controls.Add(Type:=msoControlButton, Temporary:=True)
            .Caption = "Final"
            .OnAction = "Final"
            .FaceId = 1156
            .BeginGroup = True
        End With
    End If
End Sub

Public Sub Workbook_SheetDeactivate(ByVal Sh As Object)
    On Error Resume Next
        Application.CommandBars("Cell").Controls("Send").Delete
        Application.CommandBars("Cell").Controls("Final").Delete
    On Error GoTo 0
End Sub