From your description, I'm guessing it's a type of electronic heater with a steel covering as opposed to a traditional glass one. I've never personally heard of this brand before, nor its reliability. Your best option would be to go with a more common, well known trusted brand, like Marineland or Eheim.
Like the previous comment before me, I personally use Marineland Stealth heaters as well. Ebo-Jager (by Eheim) heaters are just as reliable, and are cheaper. The Stealth is plastic-coated and shatterproof, even if you dunk it dry-running into ice water. It's also easy to hide, hence its name, 'Stealth'.
Note that Visi-therm heaters and Stealth heaters are two different things. They are both heaters made by Marineland. The Visi-Therm Deluxe is a glass heater with a highly visible temperature control and a pilot light (like most heaters). The more expensive Stealth is completely black (except for the knob), and is made of a plastic exterior. It uses an aluminum heating core instead of a traditional ceramic one.
Hands down, the Stealth is the best heater (in my opinion) on the market. It's well worth the above-average price.
A 200-watt is enough unless your tank temperature dramatically differs from your room temperature.
Good Luck, and Happy Fishkeeping!
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