First off.... I installed this on a older 1000L hotub. My old analog heater died and I didn't want to spend the 1000+$ to put a modern heater and controller in it. This was the only heater thermostat combo I could find. Installation was easy and straightforward. Instructions where there but basicly useless as the English on them was so broken you could easily tell its from off shore (probably China)
My issues. First and foremost is the temp. Leave the temp dial in the same spot and it fluctuates anywhere from 98-106 deg Celsius.
Secondly the internal breaker pin trips every couple weeks or so (only in winter when it's working harder as my tub is outside but we'll insulated) I wouldn't recommend it to anyone unless the temp does not require to be that specific. If whatever your using it for does not require a specific temp then it's great value but you get what you pay for.