I had something like that from IKEA. I thought I was pretty slick using in the boil pot to monitor temps during cooling. I can't remember if it was the first or second use but I was running my ice water and pump through my immersion chiller and it would not get below a certain temp. I do not know how long I sat there looking at the same temp before I realized. It Usually takes around 10 minutes to cool. Turns out the element had gotten damaged and stuck at whatever temp and I had cooled my wort way below pitching temp. It is a nice idea setup by I no longer for cheap options to accomplish this. Timers are cheap, get a temp probe designed for the conditions you will be putting it in.