308 Smoothing At Waist Brief
£19.00
308 Smoothing At Waist Brief
£19.00
Color: True Red
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This is the first collection of at waist shapewear that will do the job. Designed and created using unique yarns that control, feel super lightweight and manage moisture, all while making you feel like you are just wearing undies.
- Lightweight smooth wear - for everyday
- Level 1 shaping
- 2 Ply waistband comfort
- No digging in - no VPL
FABRIC & CARE
Fabric: 95% Nylon / 5% Spandex
Care instructions: Machine wash cold. Do not use softeners. Use non-chlorine bleach if needed. Tumble dry or line dry
Customer Reviews
2,836+ Women Can’t Be Wrong
“I’ve been searching for underwear that smooths without squeezing for years. This is it. The waistband sits perfectly, no rolling, no digging. I wear them every day and I’ve ordered six more pairs in different colors.”
“These are the most comfortable underwear I’ve ever owned. They’re not shapewear — they just make everything look smoother. I wore them under a fitted dress to a wedding and got so many compliments on how I looked.”
“I bought these with the matching bra and it’s the best set I’ve ever owned. The brief smooths my waist beautifully and I forget I’m wearing them. The 180-day guarantee meant I had nothing to lose trying them. Now I’m a customer for life.”
Join over 1 million women who have already made the switch.
Shop the 308 Smoothing BriefEngineered for Comfort
Every Detail, Designed with Intention
Three decades of intimate apparel expertise went into every stitch. Here’s what makes the 308 Smoothing Brief different from anything you’ve worn before.
The Waistband That Holds Without Marking
Most waistbands do one of two things: dig in and leave marks, or sit loose and do nothing. Ours does neither.
The 2-ply waistband is engineered at the yarn level — not compressed onto your body, but knitted to sit flat and hold. No elastic bands. No hard edges. No red marks when you undress.
Second-Skin Feel. All-Day Breathability.
We don’t call this shapewear. That’s not an accident — traditional shapewear compresses. This fabric holds its shape around you, not against you.
The result is something most women describe the same way: you forget you’re wearing it. Your waist doesn’t.
Seamless Silhouette
No raised seams, no visible lines, no panty outline under clothes. The 308 disappears under everything — fitted dresses, tailored trousers, lightweight fabrics. You'll forget you're wearing it. Your clothes won't show that you are.
308 Smoothing Brief
Built for Every Day —
Not Just the Days
That Need Shapewear
Most smoothing underwear is occasion-wear. You pull it out for events. You suffer through it. You take it off the moment you get home and swear you'll find something better.
The 308 Brief was designed for Tuesday. For the commute, the desk, the school pickup, the errand run, the dinner out. Wear it every day — wash it every night — and it holds its shape, wash after wash.
The commute.
7am to 10pm.
Back-to-back
meetings.
The errand run.
No adjusting.
Dinner out.
Forgot it was on.
The long day.
Still there at 10pm.
20+ Colors
Match your undertones, coordinate your wardrobe, or just pick the one that makes you smile. Same fit experience across every color.
"S" Through "3X"
SmoothKnit fabric stretches more than it looks. Order your regular size. Unsure? Order two — return one free, no questions asked.
Wash After Wash
Same structure on wash 1 as wash 100. No elastic degradation. No shape loss over time. Machine washable.
Underwear you forget you own. That's the whole point. Not shapewear you endure — underwear that works so quietly you stop thinking about it entirely.
180-Day Trial
We let you wear it,
wash it, and still return it.
We offer a 180-day free return and exchange policy. Not because we have to — because we know what happens once you actually feel the difference.
Wear it. Wash it. Live in it. If it's not the most comfortable underwear you've ever owned after 180 days, we'll take it back. No questions, no restocking fees.
We can afford to do this because the return rate is low. Women don't send these back.
FAQS
Questions? Start Here.
Everything shoppers usually want to know before trying the 308 Smoothing Brief at home.
What makes the SmoothKnit System™ different?
Most smoothing underwear blends spandex into a single layer of fabric — and that spandex is what breaks down fastest, typically within 3–6 months of regular washing. The SmoothKnit System uses a 2-ply knitted construction where the smoothing comes from the structure of the knit itself, not from spandex tension. That structure doesn't degrade the same way. Same shape, same smoothing on wash 100 as wash 1.
How does it smooth without feeling like shapewear?
Traditional shapewear compresses. The 308 Brief supports. The high-waist design and 2-ply knit create a smooth silhouette at the waist without squeezing or restricting movement. You can wear it all day — through meetings, errands, evenings out — and forget it's there.
What size should I order?
SmoothKnit fabric stretches more than it looks. Order your regular size. Unsure? Order two — return the one that doesn't fit for free. We cover the shipping both ways, so there's no risk in trying.
Will it show lines under clothing?
No. The seamless construction and smooth-edge waistband are designed to disappear under everything — fitted dresses, tailored trousers, activewear. No lines, no bulk, no visible waistband ridge.
Does the waistband roll or dig in?
The 2-ply waistband is engineered at the yarn level — knitted to sit flat and hold, not compressed onto your body. No elastic bands. No hard edges. No red marks when you undress. Customers consistently report the waistband stays exactly where it starts, from morning to night.
What is the 180-Day Try-at-Home policy?
We offer 180 days for returns or exchanges. Wear it, wash it, try it for real. If it's not the most comfortable underwear you've ever owned, send it back. We pay the shipping both ways, no questions asked.
What is the fabric and how do I care for it?
The 308 Brief is made from 92% Nylon / 8% Spandex. Machine wash cold. Do not use fabric softeners — they coat the fibers and reduce breathability. Use non-chlorine bleach only if needed. Tumble dry low or line dry to preserve the SmoothKnit structure.
Our Story
Designed by the people who built the industry
Our founders spent 30+ years designing bras for Victoria’s Secret, Nike, Spanx, Lululemon, Triumph, Maidenform and more. They know what works — and they know what women actually want. Now they’re bringing that expertise directly to you.
Expert Craftsmanship
Every bra is the result of decades of intimate apparel engineering. Perfected fit for millions of women worldwide.
Women-First Design
Every detail is made for real bodies and real life. We design for how women actually live — not how they’re supposed to.
Trusted by 2M+ Women
Over one million customers have made Underoutfit their everyday essential. Join a community that knows what comfort really means.
“A bra to forget. — that’s not a tagline. It’s the standard we hold ourselves to every single day.”
Our Promise to You
180 Days to Fall in Love
We’re so confident you’ll love our garments that we give you 180 days to decide. Wear it, wash it, try it again. If it’s not right, return or exchange it — completely free.
- 1 Order your size — or try two sizes at once
- 2 Wear it, wash it, wear it again
- 3 Not right? Return or exchange — free, for 180 days
Wash & Wear · Free Returns · Free Exchanges