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FreeFlex™ Demi Bra
FreeFlex™ Demi Bra
$68.00
USD
2 for $90
Our first underwire bra
Comfortable, flexible wire
Lifts and separates
Lightly lined molded cups
Size and Fit Guide
Use Our Calculator to Find Your Traditional Bra Size
Step 12 of 2
Your Results
Measure Your Under Bust
Measure Your Full Bust
Wearing an unpadded bra, wrap a measuring tape around the top of your ribcage. You’re looking for a snug fit - so we recommend tightening on the exhale and noting the smallest measurement to the decimal.
Wrap the measuring tape around the fullest part of your chest, making sure the measuring tape is paralell to the floor. Relax your shoulders and measure where it falls.
At Knix, your size is
Still have questions? Ask our virtual assistant about finding the perfect fit.
Still have questions? Reach out to info@knix.com to learn more about our sizing.
Rewards Members Earn
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Product Description
The Underwire Bra Reinvented
Wear tested for over 625 hours, providing unparalleled lift, separation, and support.
All Day Comfort
It's everything you want from an underwire bra without the downfalls of one.
Feels Made For You
Lightly lined, molded demi cups lift and separate for a great shape that looks amazing under lower necklines and T-shirts. Adjustable straps create the perfect fit.
Smooth Coverage
The ultimate t-shirt bra that appears invisible under clothes.
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How to Choose?
Essential
- • Days you don’t need leak protection. Everyday freshness and moisture wicking.
-
0 tsp
Heavy
- • Extra peace of mind. For the first days of your cycle, light bladder leaks, or a full night's sleep without a leak.
-
about 8-14 tsp
-
about 1.5-3 regular pads
-
about 4-7 super tampons
-
about 1.5-3 menstrual cups
Light
- • Daily freshness. For sweat, discharge, period spotting, or backup protection.
-
about 1-3 tsp
-
about 1-3 pantyliners
-
about 1-3 regular tampons
-
about 0.5 menstrual cups
Moderate
- • For mid-cycle flow, surprise cough or sneeze leaks, or a really sweaty spin class.
-
about 4-8 tsp
-
about 1-1.5 regular pads
-
about 2-4 super tampons
-
about 0.5-3 menstrual cups
Ultra
- • Ultimate peace of mind. For the heaviest period days, light bladder leaks, unexpected postpartum flow, or overnight protection.
-
about 15-20 tsp
-
about 1.5-2.5 super pads
-
about 7-11 super tampons
-
about 2-3 menstrual cups
How it Compares
Shape & Smooth Bra
Molded cups for lift & support
Mesh detailing at bust to prevent spillage
Back mesh panels for a smooth silhouette
WingWoman Contour Bra
Molded cups lightly lift & separate
Extra side coverage prevents spillage
Comfortable, wireless support
Revolution V-Neck Bra
Wireless, removable cups
Buttery-soft BeyondSmooth™️ fabric
Four-way stretch for total comfort
Uplift Push Up Bra
Embedded raised foam panel for natural lift
Molded cups define your shape
Comfortable, wireless support
FreeFlex™ Demi Bra
Comfortable, flexible underwire
Lightly lined cups
Lifts and separates
Revolution Shadow Mesh Bra
Wireless, removable cups
Buttery-soft BeyondSmooth™️ fabric
Mesh detail at bust prevents spillage
Revolution Scoop Bra
Wireless, rounded cups
Buttery-soft BeyondSmooth™️ fabric
Versatile scoop neckline
FREEFLEX™ TECHNOLOGY
Carbonized Flexible Wire
Rigorous Comfort Testing Wear
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Recently Viewed
Total 5 star reviews: 247 Total 4 star reviews: 73 Total 3 star reviews: 57 Total 2 star reviews: 58 Total 1 star reviews: 53
What our customers are saying
Generated by AI from 100 most recent customer reviews
Last updated 3 weeks ago
Customers say this underwire bra offers excellent comfort and support for many users, with several praising it as the most comfortable underwire bra they've owned. Many reviews mention the soft fabric and good lift it provides. However, common feedback includes a significant squeaking or creaking noise from the underwire that occurs with movement, which many find annoying and noticeable to others. Frequent comments address sizing inconsistencies, with some finding it runs small while others experience gapping or poor fit. Several users note discomfort at the center gore area between cups, and some mention strap adjustment issues. While many customers became repeat purchasers and highly recommend it, others found the noise and fit problems made it unwearable despite the comfort.
67%would recommend this product
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488 reviews
- Rated 5 out of 5 stars35 minutes agoFinally back to underwires!
I swore off underwires. The digging, the pinching, the discomfort. But let’s be honest, nothing lifts and separates like underwire. I took a chance and tried the Knix Demi and I’m obsessed. It’s comfortable and fits perfectly, like all of my other wireless Knix bras. But this one makes me feel so much more feminine. The only downfall is it’s a little “squeaky” but I’m hoping that fades with time. Please make some more fun colors in this bra! I will keep buying them!
KUKnix US 2.029 seconds agoHey Beth!
We're so thrilled you're obsessed with the FreeFlex™ Demi! Love that you found the perfect balance of comfort and lift. More fun colors are definitely on our wishlist too!
Team Knix
Beth N.Verified BuyerReviewingFreeFlex™ Demi Bra - Rated 5 out of 5 stars5 hours agoI will only ever buy this bra!
Beautiful quality and fit! So comfortable.
KUKnix US 2.05 hours agoHey Maxine!
This made our day! We're so thrilled you're loving the quality and comfort of our FreeFlex™ Demi Bra. There's nothing better than finding your perfect bra!
Team Knix
maxine b.Verified BuyerReviewingFreeFlex™ Demi Bra - Rated 1 out of 5 stars5 days agoNot the bra's fault.
I would have returned this bra but it was a final sale. As in my previous review for the Revolution mesh bra, I don't believe it is the bra's fault but rather my post menopausal body. I found the underwire was comfortable but it did nothing to enhance my form. I will be donating this bra to our local benevolent fund. Again, I found the quality to be good but just not a good fit for me.
Jennifer P.Verified BuyerReviewingFreeFlex™ Demi Bra - Rated 2 out of 5 stars5 days agoSqueaky
I had high hopes for this bra and I may have loved it if the squeaky underwire didn't drive me crazy! I just couldn't get past it. That being said, the customer service i received after pointing out the issue was top notch.
Cherie C.Verified BuyerReviewingFreeFlex™ Demi Bra - Rated 5 out of 5 stars6 days agoGreat support
Perfect for any v neck tops..
Smooth underTShirts also love
It
Pat Z.Verified BuyerReviewingFreeFlex™ Demi Bra - Rated 5 out of 5 stars1 week agoNice bra!
This bra is comfy, and unlike the Wingwoman (which I still love) it separates as well as supports. Game changer - I'm finally back to wearing underwire again after all these years!
Karen D.Verified BuyerReviewingFreeFlex™ Demi Bra - Rated 5 out of 5 stars1 week agoForever a Knix fan
I love this set so comfy and good material. I’m obsessed with my knix sets
alicia S.Verified BuyerReviewingFreeFlex™ Demi Bra - Rated 3 out of 5 stars1 week ago3 Stars
These bras did not fit my large chest. I really wanted to love them though.
AlyseReviewingFreeFlex™ Demi Bra - Rated 3 out of 5 stars1 week ago3 Stars
These bras did not fit my large chest. I tried multiple sizes. I really wanted to love them though.
AlyseReviewingFreeFlex™ Demi Bra - Rated 3 out of 5 stars1 week agoSqueaky
I always rely on reviews. I have a few knix bra styles and have found them to fit slightly larger than what I normally wear. This one is the exception to that rule. I initially ordered a size down (based on my experience) and had to return to get my true size. Knix was great and no issues. Except that this bra squeaks. The underwire in the centre as well as the sides play a symphony of squeaks. It’s definitely not a 12hr shift bra but I can manage 8hrs. It certainly lifts and supports.
Erin O.Verified BuyerReviewingFreeFlex™ Demi Bra - Rated 1 out of 5 stars1 week agoFree flex Demi bra
Size was correct. 36 a but after wearing it all day I couldn’t wait to take it off. The wires rubbed me inbetween my breast’s. The most uncomfortable bra Knix has ever made. Disappointed I ordered two. One was damaged. Should have gotten a refund. When I tried it on it felt great. But after a days wear I was in pain.
Richelle G.Verified BuyerReviewingFreeFlex™ Demi Bra - Rated 5 out of 5 stars1 week agoLove
This bra fits perfect , no gaps,
Comfortable, seamless
Give u a little cleavage
Looks smooth under
Clothes I am totally hooked on these bras
Pat Z.Verified BuyerReviewingFreeFlex™ Demi Bra
