It's just a cheapo Aqueon 10 watt mini heater. From what I've read (since purchasing) they really aren't the highest quality, and a bunch of them come out of the package not working.. However, I guess I'm a lucky gal, because mines always worked great.
Good to know. I have been wanting to breed my neon tetras in my 2.5 gallon but I wasn't sure how I was going to heat it. I wish I could get away with not heating it.... but that's another topic.