Provide your tank with the proper temperature with the most advanced heating technology available. THEO heaters are designed with a peculiar cylindrical shape that renders them virtually shatterproof. Fully submersible, THEO heaters function with the PTC (Positive Thermal Coefficient) heating element, a special polymer sheet silk-screened with heating ink (like your car's windshield defroster), that enables them to run dry for a short time without damage. With an easy-to-read temperature dial, these heaters are the simplest, yet safest available.
Very pleased, does a great job in my Fluval Edge 6 gallon.
Really powerful little heater 6/12/2013
Reviewer: Brian C.
I bought this heater to use in my Fluval Spec V nano reef tank. This thing is GREAT! Heats up the water quickly, and its slim profile fits in the pump chamber with room to spare, although I had to nix the suction cups (no big deal, though). I highly recommend.