Secures the cab doors against unauthorised opening. If one of the cab doors is opened while Guard-plug is placed in the cigarette lighter socket, the alarm sounds immediately. All doors that switch on the interior lighting can be secured with a guard-plug.

Technical data: Power supply 12/24V DC, current consumption approx. 20 mA, alarm tone approx. 90 dB (int. siren), temperature range -10°C to +80°C, weight approx. 45 g.