To be used only on dry hair. They are heated either electrically or by steam, and they are a great time saver in the salon.Follow the same setting patterns as with wet setting, but allow the hot roller to stay on the hair for about 10 min. A thermal protector can be sprayed on the hair before setting. The result is a curl that is weaker than a wet-set curl, but stronger and longer lasting than can be achieved using a curling iron. Spray on products to each section of the hair to create a stronger set.