Automatic aquarium heater?thermo-wave?50W?

I found this about 8" and its in a long tube shape...it says "automatic aquarium heater for household use only". It says 50W 120 volt 60Hz 19H50-8(S) on it.... has a cord off it and a little knob that goes to LO and HI temp... and on the same end as that it has a little thing that says "MINI WATER LEVEL". in bold letters it says THERMO-WAVE with a fadded B.... what is this? can it go in water? plz i tried googling it and i cannot find anything on it!