Curling and straightening hair requires the stylist to use a curling rod or a flat iron to get a desired look. These irons use heat to manipulate the hair into a variety of waves, curls and reversing natural curls and temporarily straightening the hair. Straightening or even curling hair can damage it due to direct heat from the iron and applying chemicals afterwards to keep its shape. There are irons that have a function to straighten or curl hair even when it's damp (from showering or wetting the hair), but this requires more heat than the average iron (temperatures can range from 300 to 450 degrees). Heat protection sprays and hair-repairing shampoos and conditioners can protect hair from damage caused by the direct heat from the irons.