my $face = "DejaVu Sans Mono"; # Spaces and other non-ASCII chars are allowed
my $desc = $mw->Label (
    -text       => "SmartCheckin",
    -font       => "{$face} 128 bold",
    -width      => 14,
    -anchor     => "w",
    -relief     => "groove",
    -background => "grey",
    )->pack;