Mori · licensed hairdresser, 8 years in Tokyo & Shanghai, specialising in Japanese straightening.
Matching a product to a hair type was the job. That is what this article is.
The ReFa BEAUTECH DRYER SMART W is the Japanese dryer readers outside Japan ask me about most. It is light, it folds, it runs on 100–240 V, and it promises to keep the air below a set temperature so you cannot overheat your hair. It is also not sold on Amazon US, so buying one means importing it.
Below: what the SMART W actually does (including one thing it is often misread as doing), how to avoid the wrong model, what owning one in the US is like, and which hair it is worth the trouble for — plus what to buy here if it is not.
⏱️ In a hurry?
Fine, bleached or chemically straightened hair, and you will import → ReFa BEAUTECH DRYER SMART W (model RE-AX, 100–240 V)
You want the same gentle idea, bought on Amazon US → Panasonic EH-NA2C nanoe Compact
You want a travel dryer with a US warranty → Dyson Supersonic Travel
You want a sensor that protects the scalp, bought here → Dyson Supersonic Nural
Thick, long or curly hair → skip the SMART W; take the Panasonic EH-NA67 nanoe
Never buy for a US outlet → ReFa SMART (RE-AN) or ReFa PRO (RE-AJ) — both 100 V
Quick Comparison
| Line | Weight | Built for | Price | Check Price on Amazon |
|---|---|---|---|---|
| ReFa BEAUTECH DRYER SMART W · RE-AX · 100–240 V | 520 g with cord, 1,150 W | Fine, bleached or straightened hair; sensitive scalps; travel | $$$ | Not on Amazon US — import only |
| Panasonic EH-NA2C nanoe Compact · US 120 V | Folding, 1,400 W | Fine to medium hair; the closest gentle option sold here | $ | Check Price on Amazon |
| Dyson Supersonic Travel · dual voltage | Compact | Frequent travellers who want a US warranty | $$$ | Check Price on Amazon |
| Dyson Supersonic Nural · US 120 V | Full-size | Sensitive scalps, bought and serviced in the US | $$$$ | Check Price on Amazon |
| Panasonic EH-NA67 nanoe · US 120 V | Full-size, 1,875 W | Thick, long or curly hair; diffuser included | $$ | Check Price on Amazon |
| ReFa SMART (RE-AN) / ReFa PRO (RE-AJ) · 100 V | 475 g / 740 g with cord | Japan only — not for US outlets | $$$ | Not on Amazon US — do not import |
Price bands: $ budget · $$ mid-range · $$$ premium · $$$$ flagship or import. Check the live listing for today’s price.
What the SMART W Is, in Plain Numbers
MTG, the company behind ReFa, released the SMART W in Japan on 21 February 2024 as the multi-voltage version of its compact SMART dryer. The W is the part that matters to you: according to MTG, the main difference from the plain SMART is that the W runs on AC 100–240 V.
The specifications MTG and Japanese retailers publish:
- Model numbers: RE-AX-02A (white), RE-AX-03A (black), RE-AX-05A (pink), RE-AX-20A (ivory)
- Power: AC 100–240 V, 50/60 Hz · 1,150 W on HOT and HIGH
- Airflow: about 1.0 m³/min on HIGH, about 0.7 m³/min on LOW
- Weight: about 520 g including the cord, without the nozzle
- Size: about 230 × 49 × 209 mm, folding handle · cord about 1.7 m
- In the box: one styling nozzle — no diffuser
- Safety: motor and heater stop automatically after 60 minutes of continuous use
The controls are simple. A slide switch chooses HOT or COOL. A MODE button sets the airflow to HIGH or LOW. A SENSE button, which only works on HOT, cycles through SCALP (aiming under 50 °C), MOIST (aiming under 60 °C) and SENSING OFF.
How the Sensing Program Works — and What It Does Not Do
This is the part most English-language reviews get wrong.
What MTG says. The SMART W has a built-in sensor that reads the ambient (room) temperature. Based on that reading it selects a program, and the program controls the air temperature automatically — switching between warm and cool air by itself — aiming to keep the hair surface below about 50 °C (122 °F) in SCALP and below about 60 °C (140 °F) in MOIST. MTG’s own FAQ says that if the sensing seems inactive, you can test it by blowing the dryer into the air instead of onto your hair.
What it does not do. It does not measure your hair. The older, heavier ReFa BEAUTECH DRYER PRO is the model with a target sensor that monitors the temperature of the hair. The SMART and SMART W replaced that with a room-temperature reading plus a pre-set program. So the dryer does not know whether you are holding it 5 cm or 20 cm from your head, or whether the section in front of it is wet or already dry. It runs a warm/cool cycle that was designed so that, used normally, the hair stays under those limits.
My professional judgement. I do not think that makes it a weaker dryer — I think it makes it an honest one. Heat damage while drying is temperature multiplied by time on wet hair, and wet hair is at its weakest (the straightening damage article explains why). A program that keeps dropping to cool air limits both sides of that multiplication without relying on you. The SMART W protects the person who does not keep the dryer moving — which, in my experience, is most people at seven in the morning.
What it cannot protect is someone who switches to SENSING OFF or holds the nozzle against the scalp. Keep it a hand’s width away and moving, as with any dryer.
Speed: The Honest Trade-off
At 1,150 W and about 1.0 m³/min, the SMART W is a modest dryer, although MTG says it dries faster than its own 2021 PRO.
The cool phases of the program add time. On short or fine hair it barely matters; on thick hair, or anything past the shoulder blades, you will notice it. For curly hair, the missing diffuser matters more than the sensing — see the curly hair products guide.
The Model-Number Trap: SMART W vs SMART vs PRO
ReFa sells several dryers with almost the same name, and export listings do not always state the voltage. Japanese plugs have the same two flat pins as US plugs, so a 100 V dryer will fit a US outlet — and run over-voltage, risking the dryer or worse.
- ReFa BEAUTECH DRYER SMART W — model RE-AX, AC 100–240 V. The one to import.
- ReFa BEAUTECH DRYER SMART — model RE-AN, AC 100 V. Looks almost identical. Japan only.
- ReFa BEAUTECH DRYER PRO — model RE-AJ, AC 100 V, about 740 g. Japan only.
- ReFa BEAUTECH DRYER BX W — ReFa’s newest flagship, 100–240 V, heavier than the SMART W and priced well above it.
Before you pay, check the listing or box photo for two things: model number RE-AX and a rating of AC100–240V. Buy new, not refurbished — without a usable warranty, a second-hand unit is a gamble. Using a 100 V model in the US needs a step-down transformer rated around 3,000 W — the 100 V problem guide shows the arithmetic — and that is not a sensible way to run a travel dryer.
Owning One in the US: Plug, Warranty, Repairs
Plug. The SMART W plugs straight into a US outlet. No adapter and no transformer.
Warranty. This is the real cost of importing. MTG’s FAQ says that a fault caused by using the dryer outside the country where it was bought will not be repaired free of charge, even during the warranty period. In practice, a SMART W bought from Japan has no warranty you can easily use in the US.
Where to buy. As of October 2026, no ReFa dryer is listed on Amazon.com — I searched again for this article. The SMART W is sold by ReFa in Japan and by Japanese export retailers, so there is no affiliate link or button for it here.
ReFa BEAUTECH DRYER SMART W — Who Should Import It
Voltage: 100–240 V worldwide · Style: 520 g, folding, 1,150 W · Built for: Fine, fragile or chemically treated hair
In the salon, the hair I worried about most was bleached or freshly straightened hair — both have lost part of their internal structure. For that hair, a dryer that limits its own heat is worth the slower drying and the missing warranty. MTG’s recommended routine is SCALP first, then MOIST for the lengths, then COOL on LOW to finish — and I would follow it.
Who it is for
- Fine, bleached or chemically straightened hair
- Sensitive scalps that sting after blow-drying
- People who travel abroad and want one dryer for every country
Who should skip it
- Thick, coarse, very long or curly hair — too slow, and no diffuser
- Anyone who wants a US warranty and an easy return
Pair it with a gentle wash routine. A low-heat dryer does not help much if the shampoo strips the hair first — see the aftercare guide for straightened hair. If you also use a flat iron, the Japanese flat iron comparison covers the other heat tool.
Panasonic EH-NA2C nanoe Compact — The Gentle Option You Can Buy Here
Voltage: US 120 V · Style: Folding, 1,400 W · Built for: Fine to medium hair
The EH-NA2C has no temperature program, but it has an oscillating QuickDry nozzle that keeps the airflow moving so no single spot takes the heat for long. Of the Japanese dryers sold on Amazon US, it is the closest in spirit to the SMART W: compact, modest power, hard to overheat a section with. The Panasonic vs ReFa comparison goes deeper into the two approaches.
Who it is for
- Fine or thin hair, and people who want a Japanese dryer without importing
- Small bathrooms and domestic travel
Who should skip it
- Thick or curly hair — under-powered, no diffuser
- International travel — it is 120 V only
Pair it with medium heat, not high. The nozzle spreads the heat; it does not cap it.
Dyson Supersonic Travel — The Travel Dryer With a US Warranty
Voltage: Dual voltage · Style: Compact · Built for: Frequent flyers
If what draws you to the SMART W is that it works everywhere, the Supersonic Travel does the same job and is sold and serviced in the US. It keeps Dyson’s heat control, which stops the air temperature spiking, but nothing drops it to cool air by itself. The ReFa vs Dyson comparison sets the two side by side.
Who it is for
- People who fly often and want one dryer for every country
- Anyone who wants a US warranty more than ReFa’s heat ceiling
Who should skip it
- Very fragile hair whose owner does not keep the dryer moving — the SMART W is the more forgiving machine
Pair it with the lowest heat setting that still dries your hair in reasonable time.
Dyson Supersonic Nural — For a Sensitive Scalp, Bought Here
Voltage: US 120 V · Style: Full-size · Built for: Sensitive scalps; people who want a sensor and a US warranty
The Nural measures how far the nozzle is from your head and, in Scalp protect mode, lowers the temperature as you get closer. Unlike the SMART W, it is actually reacting to your distance. It is the closest thing to ReFa’s protective idea that you can buy and return in the US.
Who it is for
- Sensitive scalps, and people who dry close to the roots
- Anyone who wants sensor-based protection without importing
Who should skip it
- Travellers — it is a full-size 120 V dryer
- Anyone on a budget
Pair it with Scalp protect on and medium heat for the lengths.
Panasonic EH-NA67 nanoe — If Your Hair Is Thick, Long or Curly
Voltage: US 120 V · Style: Full-size, 1,875 W · Built for: Thick, long or curly hair
For hair the SMART W is too slow for, the EH-NA67 is the Japanese-brand answer: more power, an oscillating nozzle, and a full-size diffuser in the box. The full Japanese dryer guide compares it with the rest of Panasonic’s range.
Who it is for
- Thick, long, coarse or curly hair that needs a diffuser
Who should skip it
- Frequent flyers — 120 V and full-size
Pair it with the diffuser on low speed for curls, and a cool finish.
If You Still Cannot Decide
Your hair is fine or fragile, and importing does not bother you → ReFa SMART W.
Your hair is fine or fragile, and you want to buy here → Panasonic EH-NA2C.
You fly a lot and want a warranty → Dyson Supersonic Travel.
Your scalp is the problem → Dyson Supersonic Nural in Scalp protect, or the SMART W in SCALP mode.
Your hair is thick, long or curly → Panasonic EH-NA67.
If You Live in Japan: There Is Nothing to Import
This review is written around one question — is it worth importing? — because the ReFa is not sold on Amazon US. In Japan that question disappears. Prices are Amazon.co.jp in November 2026, tax included, and move quickly — check before you buy.
The ReFa BEAUTECH DRYER SMART W (リファビューテック ドライヤー スマートW) is on Amazon.co.jp at about ¥40,000, 100 V as designed, with a domestic warranty. Everything this review says about the sensing behaviour still applies — what changes is that you are no longer paying an importer and accepting a warranty you cannot claim on.
👉 ReFa BEAUTECH DRYER SMART W を Amazon.co.jp で見る →
And the range is wider here. The S+, SE, BX and the salon-only PRO are Japan-market models that never reach Amazon US at a sensible price. If you are choosing in Japan, SMART W is one option among several rather than the only one you can get.
FAQ
Does the ReFa SMART W work in the US? Yes. It is rated AC 100–240 V, and the Japanese plug fits a US outlet without an adapter. Check that the model number starts RE-AX.
Is the ReFa SMART W sold on Amazon US? Not as of October 2026. It is sold by ReFa in Japan and by Japanese export retailers.
Does the SMART W sensor measure my hair temperature? No. According to MTG, it reads the room temperature and runs a program that switches between warm and cool air, aiming to keep the hair under about 50 °C in SCALP mode and 60 °C in MOIST mode. The older ReFa PRO is the model with a sensor aimed at the hair.
What is the difference between ReFa SMART and SMART W? Voltage. The SMART (RE-AN) is 100 V and for Japan only. The SMART W (RE-AX) is 100–240 V.
Will my warranty cover it in the US? Assume not. MTG says faults from use outside the country of purchase are not repaired free of charge, even within the warranty period.
Is it good after Japanese straightening? It is one of the best dryers for it, because it limits heat on hair that has lost part of its structure. Wait the full 72 hours before the first wash and blow-dry — the first 72 hours guide explains why.
Bottom Line
The SMART W is a gentle, light, genuinely multi-voltage dryer, and its sensing program does what it should — as long as you understand that it reads the room, not your hair. For fine, bleached or straightened hair, it is worth importing, provided you accept slower drying and no practical US warranty. For everyone else, a dryer you can buy here makes more sense.
Fragile hair, happy to import → ReFa BEAUTECH DRYER SMART W (RE-AX, 100–240 V) Gentle, bought on Amazon US → Panasonic EH-NA2C Travel with a US warranty → Dyson Supersonic Travel Sensitive scalp, bought here → Dyson Supersonic Nural Thick, long or curly hair → Panasonic EH-NA67
Prices and availability on Amazon change. Check the live listing before buying.