Purchased this 75w Eheim heater for my fish 🐟 tank, fed up of the cheap chinese Hidom models not being accurate enough with the temperature so decided to buy the Eheim as I've read alot of reviews on them mostly positive with the odd issue people have with calibration but to be honest it was very simple to do, just watch a few YouTube videos & once you have the heater installed wait 24 hours until you adjust the temperature & calibrate it to your desired temperature.