What is the difference between a hot air styling brush and a curling iron?

A hot air brush works like more like a blow dryer and brush combined, than like a curling iron. Warm air is forced through a vented barrel which has "teeth" to grab the hair and style while drying. Hot air brushes give hair volume, soft curls or waves. Hot air brushes are not intended for use on wet hair. Use one to finish styling your hair when it is 75% - 80% dry. A curling iron should only be used on dry hair and can produce tighter curl. Brush irons, like curling irons, come in a variety of barrel sizes. Some have multiple heat settings or tangle-free features.