A permanent wave, also called a perm, consist of waves or curls set into the hair. The curls may last several months, hence the name. Perms will be applied using chemical lotion in the form of an alkaline or acid, depending on the ph of the perm-lotion. The chemicals applied to the hair, which is then wrapped around rollers to produce waves or curls. The same process is used for chemical straightening or relaxing, with the hair being flattened instead of curled during the chemical reaction.