T3 SinglePass Smooth X straightener review

A beautiful flat iron that lives up to its name by creating smooth styles

T3 SinglePass Smooth X flat irons on reviewer's marble dressing table
(Image: © Future)

TechRadar Verdict

The T3 SinglePass Smooth X looks great while being highly practical. Its soft, blush design adds a nice touch, while its impressive tech and functionality makes it well suited to different hair types and styling needs. It holds its own among the best flat irons, in terms of performance, especially for curling and even though minor drawbacks, like the placement of the power button and overly sleek and flat results for thinner hair, are a shame, they shouldn't be deal breakers.

Pros

  • +

    Sleek design

  • +

    Extra-long plates for faster styling

  • +

    Beveled edges perfect for curling

Cons

  • -

    Leaves fine hair looking flat and limp

  • -

    Power button easily pressed mid-style

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T3 SinglePass X: two-minute review

Product info

Note: The SinglePass Smooth X is not to be confused with the SinglePass X. The latter has wider, 1.5in / 38mm plates better best suited for thicker hair and has five temperature settings compared to the Smooth X’s nine. Due to these larger plates, the SinglePass X is less compact than the Smooth X, but still features the same SinglePass technology and CeraGloss plates.

The T3 SinglePass Smooth X may not be at the top of my best hair straighteners list, but when you factor in its design, functionality, tech and value for money, it's not far off. I love its Satin Blush color, and the sleek, pastel pink finish isn't just stylish but practical, as it resists fingerprints and smudges. The rose-gold accents on the hinge and logo add a touch of luxury, while the color of the ceramic plates blends well with the blush tone, giving it a cohesive, high-end feel.

The plates are 1in wide and 20% longer than standard straighteners, which allows for faster styling by covering more hair in each pass. This is a bonus for my long, thin hair and it took a little over two minutes to finish straightening my whole head. Made from T3's CeraGloss ceramic, these plates also help to smooth frizz and add shine and while they might not glide as effortlessly as other straighteners, like the GHD Chronos, (learn more in my GHD Chronos review) they still perform well, especially when curling. The StyleEdge design of these plates, which give them beveled edges, also makes sure curls and waves are created without leaving creases, which is welcomed.

Measuring 11.8in / 30cm long and weighing 14.7oz / 417g, the SinglePass Smooth X is compact, lightweight and well-balanced. I was initially concerned the added length might make it cumbersome, but it was easy to move around my head during styling. The PrecisionControl hinge keeps the plates gliding smoothly without the need for excessive pressure, too, which adds to the overall comfort.

The temperature controls are located near the base of the styler, with a row of nine LED indicators representing its nine heat settings – from 260F / 127C to 410F / 210C. This range gives flexibility for a host of hair types, with lower settings ideal for fine and fragile hair and higher settings best suited for thicker, coarser textures. The SinglePass technology and CeraSync heaters inside the styler then help distribute this heat evenly, reducing the need to go over the same section multiple times and helping to minimize heat damage. This also helps create more uniform curls that last.

During my tests, the SinglePass Smooth X lived up to its name, straightening my fine, naturally curly hair with minimal frizz. However, after straightening, I found my hair looked a little too sleek and flat, which is common for finer hair like mine but was a tad disappointing.

Overall, the T3 SinglePass Smooth X holds its own among the best hair straighteners, with its sleek design, ease of use, and strong performance for both straightening and curling. Minor drawbacks like the placement of the power button, which makes it easy to accidentally change the heat setting, plus the overly sleek results for my thinner hair weren't dealbreakers for me, but did lessen the appeal. However, if you prefer a straight, smooth, frizz-free finish or your hair is long and thick, then chances are you will love it.

Read on for my full T3 SinglePass X review...

T3 SinglePass Smooth X review: price & availability

  • List price: $149.99
  • Available: US only
  • Replaces the T3 Lucea 1" flat iron

The T3 SinglePass Smooth X replaces the Lucea 1in flat iron and costs $149.99. It's only available in the US, and is only sold in a single Satin Blush color.

Its price and technology positions the SinglePass Smooth X in the mid-range of T3's wider straightener lineup. It sits below the $249.99 Smooth ID styler, which has the added feature of real-time personalized heat settings, and the $189.99 Lucea 1.5in styling iron, which has wider plates.

It then costs more, and offers more, in terms of tech and performance than the travel-friendly SinglePass Compact Flat Iron, which retails for $89.99 and has a smaller, more portable design.

The closest model to the Smooth X is the T3 SinglePass Stylemax. It has the same plate size, same SinglePass, CeraGloss and StyleEdge technology and design, and costs the same. Yet it offers more customizable temperature options, and a Curl Mode, which optimizes the heat for curls and waves.

Outside of T3, similar rivals in terms of features and design include the $160 Moroccanoil Perfectly Polished Titanium flat iron, and the £109 mdlondon Strait which has similarly long, bevelled plates and multiple heat settings but is only sold in the UK and ROI.

In comparison to most of its siblings, and rivals, the Smooth X's price – which initially felt high – represents much better value than may first appear. Largely because of its built-in tech, and design as well as its performance. You get more features with the SinglePass Stylemax for the same price, but that model is less attractive, less sleek and doesn't have the longer plates, which are a bonus on the Smooth X.

You can buy the SinglePass Smooth X in the US directly from the T3 website, as well as third party retailers like Amazon US.

  • Value score: 4 out of 5

T3 SinglePass Smooth X specs

Swipe to scroll horizontally
Power:Mains
Cord length:9ft / 2.7m
Temperature settings:9
Temperature range:260F / 127C to 410F / 210C
Plate width:0.9lb / 417g
Weight:‎11.8 x 1.2 x 3.6" / 30 x 3 x 9.1cm
Dimensions:1" / 2.5cm

T3 SinglePass Smooth X review: design

  • 1-inch wide, ceramic-coated plates
  • 9 different heat settings
  • Longer-than-usual plates

T3 is renowned for making attractive and elegant stylers and the SinglePass Smooth X is no exception. It comes in a single, pastel pink-rose color, officially called Satin Blush, and has a soft, matte finish.

This not only looks and feels premium, but means it doesn't pick up fingerprints or show up grease like black stylers tend to do. Even the plates match the main blush color, and there are rose gold metal accents on the hinge, logo and controls.

T3 SinglePass Smooth X flat irons, photographed side-on, on reviewer's marble dressing table

(Image credit: Future)

The plates are noticeably longer – 20% longer than standard – than other straighteners I've used, including the GHD Platinum Plus, but are on par with plates on the mdlondon STRAIT. They're made from what the brand calls CeraGloss ceramic, which is ceramic material coated in a gloss-like finish.

This is the default for plates across the T3 straightener range and has been designed to smooth frizz and add shine without snagging or pulling the hair. In my experience, this works well and while it's not the smoothest flat iron I've tried (that prize goes to the GHD Chronos) it does a great job.

These plates also use a so-called StyleEdge design. This means their edges are beveled and smooth making them great for creating curls and waves without causing creases or kinks.

Close up of ceramic straightening plate on T3 SinglePass Smooth X flat iron

(Image credit: Future)

In terms of size, the plates are one inch wide and the overall dimensions of the straightener is ‎11.8 x 1.2 x 3.6 in / 30 x 3 x 9.1 cm in size. It weighs 14.7 oz / 417g. This makes it compact and light enough for easy handling and for packing in a suitcase or bag, without being too small to work on longer hair.

I found the straightener to be well-balanced. I was initially concerned that the added length would cause my wrist to ache or be slightly cumbersome while moving it around my head, but this wasn't the case. It isn’t too heavy, but it has enough weight to feel sturdy and comfortable.

The PrecisionControl hinge keeps the arm tension just right, allowing for a smooth, even glide without any stiffness or looseness. You don't have to squeeze too hard to get the best results, nor do the plates aggressively spring back into position. This all adds to the premium feel.

The Power button on the Smooth X doubles up as a temperature control and is found near the base of the styler near the 360-degree, 9ft / 2.7 meter swivel cord. Above this button is a slim row of nine LEDs, each one representing a different temperature setting as follows:

  1. 260F / 127C
  2. 280F / 138C
  3. 300F / 149C
  4. 320F / 160C
  5. 340F / 171C
  6. 360F / 182C
  7. 380F / 193C
  8. 400F / 204C
  9. 410F / 210C

The lower settings (1-4) are designed for fine or fragile hair, the medium settings (5-6) are better for normal or "medium-textured" hair, while the 7-9, high settings are ideal for thick or coarse hair. That said, T3 does suggest dropping the temperature down 1-2 settings if your hair color-treated.

Close up of power switch T3 SinglePass Smooth X flat irons

(Image credit: Future)

When the straightener reaches your chosen temperature, the flashing lights turn solid to let you know it's ready to use. The Smooth X will then remember your chosen setting for the next time you use it. A small downside is that the position of the power button makes it easy to accidentally change temperature mid-style.

If you have thicker or longer hair, or your hair has been damaged from chemicals or over styling, you'll likely get much more use and benefit from having a wide temperature range. I've never been overly fussed about having a range of temperatures choices as my fine hair is pretty malleable. However, I welcomed the ability to drop or increase the heat as and when needed.

Features-wise, the Smooth X uses the same SinglePass technology found in all of the stylers in the SinglePass range. This technology uses a microchip that continuously monitors the temperature, preventing hot or cool spots. This means you can style your hair in a single pass, reducing the need to repeatedly glide over the same section. This not only saves time but helps reduce heat damage.

The CeraSync Heaters inside the styler then make sure the heat is distributed evenly across the plates for fast and consistent styling. These heaters work in tandem with the ceramic plates and SinglePass tech to keep an optimal and steady temperature. All of this combines to make the Smooth X a good-looking, easy-to-use and effective styler for a wide range of hair styles and types.

  • Design score: 5 out of 5

T3 SinglePass Smooth X review: performance

  • One pass is enough to smooth hair
  • Longer plates allow for faster styling
  • Excellent straightener for curling

The well-thought-out design and functionality of the SinglePass Smooth X really comes to life when you start using the flat iron for different styles and finishes. For me, with my long, thin and naturally curly hair, the extra-long ceramic plates are a particular strength. They not only glide smoothly through the hair, for both straightening and curling, but the added length and SinglePass technology means I can finish styles quickly and efficiently.

It took a little over two minutes to straighten my long hair, and I styled the majority of sections with a single pass on my preferred temperature setting of 340F / 171C, or setting 5. Technically, my hair is fine and color-treated so, based on T3's advice, I should be styling on setting 2 or 3. However, I found that while it still styled my hair well at this temperature, the style didn't hold anywhere near as well.

The consistent, even heat across the plates seemed to make a difference in speed, but also in minimizing frizz. This was particularly noticeable when curling my hair; other straighteners tend to create curls that are uneven, the Smooth X heated every part of hair and curl evenly ,meaning the shape was more uniform from top to bottom.

The beveled edges of the plates then allow for smooth curling without leaving creases in the hair, something I’ve struggled with when using other straighteners with more blocky plates. The shape, size and design of the Smooth X also makes creating waves a doddle, and the results during my tests were always polished and consistent.

T3 SinglePass Smooth X straighteners, viewed from above, on reviewer's marble dressing table

(Image credit: Future)

Sadly I was underwhelmed with how my hair looked after being straightened. This is partly due to how thin my hair is, but also, ironically, because of how well the plates glide and flatten frizz. As my hair is naturally curly, I usually only use a flat iron to knock out this frizz. I don't like to create super sleek, straight styles as they tend to leave my thin hair looking limp, flat and greasy. This was the case with the Smooth X, unfortunately.

It almost straightened my hair into submission and there was very little movement. It is possible to bring movement to straight hair without having to sacrifice a smooth finish – as I experienced with the mdlondon Strait – but the Smooth X did not achieve this balance. That said, if you have thicker hair or love sleek looks, the Smooth X will likely work exactly as you expect, and want.

Reviewer holding T3 SinglePass Smooth X flat irons with a turquoise background

(Image credit: Future)

Plus, moving the tool around my head was always comfortable, no matter which style I created. The swivel cord gives plenty of room and movement, and the weight of the straightener is balanced enough that it didn’t feel too heavy, even after styling for a while. The heat-up time is fast too, reaching setting 5 in just 10 seconds and setting 9 in 15 seconds.

I found that the power button, though convenient for switching settings before styling, can easily be pressed during use, which can be a bit annoying mid-styling. Some online reviewers have also said that the hinge tension can loosen over time, which can make it harder to maintain even pressure across the plates. I didn’t experience this myself during my review, but it’s something to keep in mind for long-term use.

  • Performance score: 3.5 out of 5

Should I buy the T3 SinglePass Smooth X?

Swipe to scroll horizontally
SectionNotesScore
ValueUpper mid-range, and decent value given the quality and features included.4/5
Design:Longer than usual plates, lots of heat settings, balanced and easy to wield.5/5
Performance:Great for curling, smooths frizz well, but can leave hair looking flat. Easy to press temperature button accidentally.3.5/5

Buy it if...

You have long or thick hair

The extra-long plates coupled with the wide range of temperatures available make the Smooth X a great choice for people with thick, long hair.

You like to curl your hair with straighteners

The Smooth X's biggest strength is the way it creates curls and waves. The long plates, streamlined shape and even heat make it quick and easy to curl your hair in minutes.

You prefer or need multiple heat settings

With nine temperature settings, you can easily adjust the heat on the Smooth X to suit your hair type and avoid damage.

Don't buy it if...

You're on a budget

While you get a lot of tech, and quality with the Smooth X, its $150 price tag may push it out of the reach of people on a budget.

You need a travel-friendly tool

While compact, the Smooth X's extra length means there are other, smaller stylers that may be better for travelling. It's also not dual-voltage, which can be limiting for international travel.

You have short or mid-length

The Smooth X's extra-long plates are welcome for long and thick hair but if you have a style that takes little effort, you may not need the longer plates.

How I tested the T3 SinglePass Smooth X

  • Tested a range of temperature settings
  • Created a range of straight and curly looks

For my T3 SinglePass Smooth X review I spent a month using it as my main hot styling tool. I created a series of different looks for different occasions including straight, curly and wavy styles and put a range of temperature settings to the test. I timed how long the styles took to complete and monitored the finish and condition of my hair.

First reviewed: September 2024

Victoria Woollaston

Victoria Woollaston is a freelance science and technology journalist with more than a decade’s experience writing for Wired UK, Alphr, Expert Reviews, TechRadar, Shortlist and the Sunday Times. She has a keen interest in next-generation technology and its potential to revolutionise how we live and work.