A hair dryer's attachments: what the nozzle and the diffuser do, and why the cool button matters most

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Researched. We have not used this one long enough to give you a verdict, and we would rather say so than invent one. What follows is how it works, who it suits, and what it will not do. When we have used it properly, this page carries the verdict and the date.

slopehill 1800W Ionic Hair Dryer

A hair dryer dries hair with two things: moving air and heat. Of the two, air does most of the work and heat does most of the damage. Almost everything worth knowing about using one well follows from that.

What the numbers say

According to the listing, this is an 1800-watt dryer with a motor that reaches up to 21,000 rpm, with three heat settings, a speed control and a cool-shot button. It is described as compact and light. Those are the specifications of a solid everyday dryer — enough airflow for thick hair, without being a salon machine.

The concentrator: for smooth

The box includes two concentrator nozzles — the flat, narrow attachments. A concentrator squeezes the airflow into a narrow stream you can aim. Pointed down the length of the hair, from root to end, it pushes the outer layer of the hair flat, which is what makes a blow-dry smooth and shiny.

Without one, the air goes everywhere, the hair gets blown around, and the outer layer is roughed up. That is where a lot of frizz after blow-drying comes from.

The diffuser: for curls

The diffuser is the wide, bowl-shaped attachment with prongs. It does the opposite of a concentrator: it spreads the airflow out and slows it down, so curls and waves dry without being blown apart. Cup sections of hair in the bowl, hold still, and move to the next section rather than moving the dryer around. For natural curl, it is the most useful attachment in the box.

The cool button

Hair takes its shape as it cools, not while it is hot. A blast on the cool setting at the end of each section sets that shape and helps it last. It is the button most people never press, and it costs nothing in heat.

Using the heat

Medium, not maximum. Keep the dryer moving and several inches from the hair, and start drying when hair is damp rather than soaking — towel-dry or let it air-dry for a while first. Put a heat protectant on before you start. We explain what those do in what the temperature on a heat protectant actually means.

On the other claims

The dryer is sold as ionic. Ionic dryers are said to cut drying time and static, and they may help a little with flyaways; the effect is modest. The listing also describes a fault-diagnosis chip, a long motor life, and low radiation. We would not weigh the last of those either way in choosing a hair dryer.

What it will not do

It will not protect hair from heat by itself — that depends on how hot and how close you go. It will not give a salon blow-dry without a round brush and some practice. And ionic technology will not turn frizzy hair smooth on its own; the concentrator and technique do more.

The product

A compact 1800W ionic dryer that comes with both kinds of attachment and a cool-shot button — which is to say, everything needed to dry hair well, if you use them.

The one people are searching for is the slopehill Professional Ionic Hair Dryer, 1800W.

slopehill 1800W Ionic Hair Dryer

We do not print prices here, because a price we typed last month is a price that is wrong today.

Written by CatieH, who covers nails and hair here.