... aviation engine pre-heater5,Remote Control for Airplane Preheater6,Aircraft pre-heater remote control control system 7,Remote control switching of irrigation systems, water ... or off by sending the GSM-RKEY a text message command, a confirmation text can be returned if requiredThe relays can ... 18 hours by sending the GSM-RKEY a text message command, a confirmation text can be returned when the relays ...