The front and lower panels are engraved the detailing shows that the Lat/Vert markings have been removed and replaced by a 'Stereo Link' switch. The two coloured lights on the lower service panel indicate Normal and Hot operating temperature. An on-board temperature sensor monitors your equipment and displays a simple electronic traffic light system that warns the user on the lower panel that the unit is becoming hot +60 deg. Of course your tube equipment will work shortly after switch on but as with all electronic tube equipment there is a nominal 'warm-up' period of about 15/20 minuites whilst your equipment stablizes for optimum working. A 1U rack mounted fan unit can be provided.