I am selling my GSM / SIM card operated controller that I use to operate my engine heather from home.
I use a T-Mobile pay-as-you-go card which costs me $3/mth. I send the controller an SMS message indicating the time I want the heather to be switched on for, and the controller sends me a confirmation.
The controller is available from the end of March
when I move my aircraft to a warmer area and I no longer need the engine pre-heater.
I am asking $260 with free shipping to the 48 lower states.