The transformation with KeraStraight Ultimate Treatment stabilises from 178°C/352°F, so do not iron below 180°C/355°F.
The maximum temperature to iron the hair at is 230°C/450°F
The greatest results are achieved when the hair is ironed slowly at the highest temperature that is healthy for the hair.
The hair has more structural integrity when ironed in 2 - 3 cm sections. Slower passing of the irons ensures even heat distribution and best results. The thicker the hair, the slower the irons need to pass through the hair.
Lower the temperature of the irons and reduce the number of passes for ends that are dryer and weaker.
It is sometimes necessary to work with two sets of irons if you have very weak ends and very resistant, curly roots.