The 1.5 inch size is NOT recommended for fine or curl-resistant hair. Those with curl-resistant hair will get better results with the 1 inch or 1.25 inch sizes. The 1.5 inch size creates loose waves, not curls. Curls not lasting? You can blame your low-end single-heater curling iron. Most curling irons lose heat after every curl so using them can be frustrating and time-consuming. Even heat is the key to getting easy and long-lasting curls, beach waves and volume. This is where our Professional-Grade Dual Heater System saves the day. With even and constant heat from the base of the barrel to the top, your style will be set to last all day long.