10 years ago I had a 50 gallon tank with a 10" oscar. He made a hobby of running in to the heater and breaking it, after the 5th one I went looking for some thing unbreakable. The sales clerk told me that there was no way the ebo jagers could be broken. To prove this he smacked the heater on the counter as hard as he could and it did not break. That was it, I was convince and that is the only heater I have ever run since.