The powerful curling iron included with the 4P Curling heats up to 400 degrees Fahrenheit to allow you to curl or wave your hair quickly and easily. The set includes 4 different size interchangeable barrels to create different types of hair styles at your convenience. Use the largest barrel (32/32) for large, loose waves. For large voluminous curls go for the 25/25 medium size barrel. For medium relaxed curls we advise the 19/19 medium sized barrel. And for full curls and defined waves use the smallest, tapered barrel (18/25).