Bombshell Ceramic Thermal Round Brush — 43mm

The middle of the three ceramic barrels, and the one to buy first. At 43mm it is wide enough to stretch a section smooth and narrow enough to leave a soft bend at the ends rather than a blunt line. If you are choosing between the three without a stylist in front of you, choose this one.

Go up to 53mm if your hair is long and you want it dead straight and polished. Go down to 33mm for short hair, a fringe, or a springier curl.

How it is measured

The 43mm is the barrel itself, engraved on the end of the brush, which is how thermal brushes are sized. That is not the same convention as the wooden round brushes in this range — those are measured bristle tip to bristle tip. Do not compare the two numbers directly.

Ceramic does the opposite of wood

A birch barrel stays cool, so the hair only ever meets one heat source. A ceramic barrel is designed to take heat from the dryer and hold it, and the section sets in the shape it cools in — the same reason a pressed shirt keeps its crease.

That is also why it settles frizz. Heat softens the bonds inside the hair while the section is wrapped and under tension, and the shape it holds is the shape it had when it cooled.

Neither material is better. They are two tools for two jobs, and anybody telling you otherwise is selling something.

How it is built

The barrel and the ferrule are moulded in one piece. No collar, no glue, and therefore no seam at the neck — which is exactly where round brushes usually snag and where they usually fail.

Vented right through, so the dryer air reaches the section instead of going around it.

How to use it

Dry down to slightly damp first. Damp hair is malleable; dry and cool, it is already set and you are only fighting it.

Section, wrap, and aim the dryer along the hair toward the ends rather than into the bristles. Then let it cool before you let go. The shape is set by the shape it was in when it cooled, not by how hot it got — a curl that drops was still warm when you released it.

Looking after it

Clear the shed hair from the base of the bristles regularly. Hair left sitting there works the bristles loose.

Wash it through with shampoo and water if you use it daily, and let it dry before you put it away.

Where it came from

Peter Louis spent twenty-three years behind a chair in Manhattan — a salon on 57th Street, and years of blowouts before that, nine in the morning until ten at night. A supplier would bring a sample, it got used on clients, and it went back with a list of what was still wrong. That went on for years until one came back right.