Is this heater any good?

[PattyCakes81]

Hi! Is the Hydor Theo 25W Submersible Aquarium Heater good?
http://www.amazon.com/gp/aw/d/B0006JLPG8/ref=ox_sc_act_image_3?ie=UTF8&psc=1&smid=ATVPDKIKX0DER#
I thinking of using it for a 2.5 gallon betta tank (my landlord saw my 20 gallon tank, and said I'm only allowed another small tank, 3 gallons and under ).

Patty

 

[Duckie]

What a nice landlord. Never heard of any landlord that would care about a fishtank - even those that have a "no pet" rule (meaning cats and dogs usually).