Portable Thermostat Control - ARE THESE ANY GOOD

[greenfingers]

wanted to know if any 1 uses these as my greenhouse is cold need to gain temperature

i found one online portablethermostatcontrol.bigcartel.com please advise me

 

[Tony O]

I got a small, plug in type as a back up on a heater. It should come on at about 38*f if the other one fails for any reason. I don't have any thing to say about it yet as it haven't been needed yet.