Does the voltage change automatically when needed?
Yes,the voltage change automatically when need(110V or 220V),so you can trave around the world with this NITION flat iron.
What is the max temp and does it work with thick hair?
Max si 450°F, it works with thick hair.
6 Options:265/300/340/375/410/450°F.
Recommend Setting as below: 265°F or 300°F for Fine; 345°F or 370°F for Medium; 410°F or 450°F for Thick;
How to operate this flat iron?
Very simple, Just One Step Operation without any buttons: Revolving the end,clockwise to power on and set the heat.anticlockwise to decrease and power off.