A cold perm, also known as a cold wave, is a hair treatment that creates curls or waves without the use of heat. Instead, it relies on chemical solutions to break and reform the hair's natural bonds. This method is popular for achieving long-lasting curls that can add volume and texture to straight hair. During the process, the hair is wrapped around rods and treated with a waving lotion, which softens the hair. After a set period, a neutralizer is applied to lock in the new shape. Cold perms are often preferred for their ability to create defined curls while minimizing heat damage to the hair.