Review on DaToo 25W Mini Aquarium Heater: Submersible Betta Small Fish Tank Heater for 3-5 Gallon Tanks - 1 Year Warranty by Matt Maxwell

Loved the shape and size but stopped working after two weeks. Glad I waited to add the fish. The temperature dropped very low before I realized it because the thermostat was wrong. I noticed this when I did a partial water change and the water was very cold. Too bad because it's a nice slim design. I also don't notice that there is no contact phone number.