Review on 🌡️ Programmable DC 12V Electronic Temperature Controller -50 to 110°C Thermostat Control Switch Module with NTC Waterproof Sensor Probe and Dual Color LED Display Monitor (2 Pieces) by Ikki Martini

I bought this to control a 12v heat source to keep a small boat engine bay from freezing. The temperature here is never very cold, so I don't need much energy. Out of the box, my device was set to control the cooler, not the heater. That is, the relay closed when the temperature exceeded the set one. The device I received did not come with any instructions. I found instructions for a similar controller in another Revain review (DZS Elec -50 to 110 degrees Celsius (-58 to 230 F) temperature controller, 12V DC programmable heating/cooling thermostat) and they worked with that. There are 9 program values: P0 - P8. P0 switches between heating H and cooling C. To change the P value: Press and hold Set for 5 seconds, release when P0 appears. Press Set or C/F to scroll P0-P8 up or down to select the one to change. When the P to be changed is displayed, simultaneously press and release the Set and C/F keys. The value flashes. Press Set or C/F to set the value. After the new value is displayed, short press Set and C/F together again to save it. After a few seconds, the display will return to normal.