Review on YukiHalu Mini Submersible Aquarium Heater With Thermometer And Temperature Controller - 25W, 50W, 100W, Or 200W Options For 5-40 Gallon Fish Tanks by Becky Gilbert

I like the size of this 50 watt heater for my 10 gallon tank. However, the cord is not long enough (about 4 feet) if you have the tank on a traditional stand. It barely reaches my surge protector and limits where I can put it in the tank. There is no red indicator light in the heater showing if it's heating so you need to be able to see the controller, and the controller is about 4 inches from the plug, so if your outlet is hard to get to this may not be for you. It also reads upside-down if you don't have it plugged in above the tank. So far it is exactly accurate, checking it with 2 different sensors over the last 2 days since putting it in. I would buy more of these heaters if the cord were about 6-8 inches longer and if it at least had an indicator light in the heater. I hope this helps others make a better informed decision. The short cord may be perfect for some people.