This seems to do what I want, perhaps? Noting the distinct lack of love in the reviews.
I am looking for something which comes on ABOVE a set temperature not below.
Application is to turn the "beer fridge" cool box on when the temperature gets up, but turn it off as the external temperature drops.
The crude approach is to run it all the time in summer, and run it during the day in spring and autumn using a 24 hour timer, and turn it off during winter.
An alternative use could be heating in the shed but I already have a thermostatically controlled fan heater (or two) lying around. Possibly to turn on an oil filled radiator or a tube heater?
Mainly looking for experience of similar devices and their reliability.
Cheers
Dave R