What it is: One 'n Only Thermal Ionic Permanent Hair Straightener is a permanent, thermal reconditioning, ionic straightening system. One 'n Only Thermal Ionic Permanent Straightener is also known as the "Japanease Hair Straightening" or "Thermal Reconditioning" system because of Conair's revolutionary thermal ionic straightening formula. Thermal Ionic, in Conair One N Only formula, reconditions hair and restructures the cuticle so your hair lies flat and straight permanently, with a brilliant, silky, shine! What it does: The hair remains permanently straight until it is cut off or permed. However, the new growth will be curly and a retouch straightening service will be required after 6 8 months, depending on the rate of hair growth and the degree of curliness of the new growth. What else you need to know: Comes in 3 formulas: Normal Formula: For use on healthy, virgin hair or hair previously colored with semi or demi permanent hair colors, processed with less than 20 volume peroxide. Resistant Formula: For use on coarse, resistant virgin hair, or resistant hair that has been color-treated using semi permanent, demi permanent or no-lift permanent hair color. Tinted / Highlighted / Bleached Forumula: For use on hair previously colored with permanent hair color processed with 20 volume or greater peroxide, bleached or double-processed hair.