HOT COMBS??

has anyone tried a hot comb on their hair, its supposed to get the very root of uyour hair, if find that its really hard to get the top of my head to be striaght becuase a normal straigtener will not go that far up your hair, anyhow my relaxer has also grown out as well, i got a very mild relaxing treatment done becuase i have wavy-curly hair, howver i now have frizzy wavy hair that i have to constantly straighten to get a decent looking head of hair, i was wondering if anyone tried hot combs? are they efficient?, as you may tell i am not of african decent, i also was wondering if it is suitable for people who do not have afro' type hair.

- please and thank you, all responses and advice are truly appreciated :):)