Well, when I got my betta / rescued my betta from wal-fart, I also bought a heater from them as well. I recommend that you DO NOT buy this heater! It did not heat the tank and was weird switching on an off for only a few minutes then it would sit for an hour or two and do nothing! The temps were 72-71 and Jose was very lethargic and slow. The box said it was an internal regulated temperature of 75-78 degrees. After about 1 week I didn't see it going on at all and it probably broke. I found a older heater that I can control the temperature and it is wonderful! Tank temps are better and Jose is more active! Below is a pic, warning, do not get even it its a low price!!!!!
I think the manufacturer is Tetramate or something like that.