







Sieve Racerback Bra in Buff
Sieve Racerback Bra
Minimal visibility. Surprising support.
Our most-requested style. A refined T-back, front closure, wireless bra, in our best-selling Sieve power mesh.
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Free US shipping on all orders from now through 12/31.
Fit
- Size Chart
- Use this as a guide. Preference is a huge factor — if you’re near the top of a size range and/or prefer more coverage, you may want to size up.
- Single T-strap back for minimal visibility under racerback or cutaway tops
- Plunging deep-V front neckline with front click closure
- Metallic front closure clicks closed so you know you're secure
- Adjustable shoulder straps and a narrow, stretch-fit bottom band
Fabric + Care
- Made from a sheer Belgian power micromesh — nipples are visible
- Buff is a caramel-y sunrise desert sands affogato tone.
- 74% Polyamide (Nylon) 26% Elastane (Spandex)
- Wireless
- Discreet metal front click closure and strap adjustment details
- Machine wash warm, hang dry, wear often
FAQ
- Price-slashed, Last Chance Sale items with a red SALE tag are direct size exchange only (no refunds).
- All full-priced, unworn items, with tags attached and in their original packaging are eligible for return or exchange within 30 days of placing your order.
- Please note, packs must be returned in full. We do not accept partial returns of packs.
- Want to know our full returns policies? Here you go.
- Want more info about shipping, materials or care instructions? Here!
Q’s on fit or sizing? Email us at hello@negativeunderwear.com




Non-Wire Bra Sizing
Your underbust: | A | B | C | D | DD | DDD | G | |
---|---|---|---|---|---|---|---|---|
24-26" | 30 | 0 | 0 | 0 | 1 | 1* | 1+ | |
26-28" | 32 | 0 | 0 | 1 | 2 | 2* | 1+ | 1+ |
28-30" | 34 | 1 | 1 | 2 | 2 | 3* | 2+ | 2+ |
30-32" | 36 | 1 | 2 | 3 | 3 | 4* | 3+ | 3+ |
32-34" | 38 | 3 | 3 | 4 | 4 | 5* | 4+ | 4+ |
35-38" | 40 | 3 | 5 | 5 | 5 | 5* | 5+ | 5+ |
38-40" | 42 | 5 | 5 | 5 | 5* |
* Non-wire bra sizing can vary by preference and if you're toward the top of a size range and prefer more coverage, you may want to size up. For styles available in + sizes (designed with additional support details for our larger cup customers), we find DD's can be on the cusp - if you prefer more coverage and support, we suggest the + bra equivalent for your band size.
Btw, the size nomenclature has changed for Bra Tops. Here's the conversion:
XS=0, S=1, M=2, L=3, XL=4, XXL=5
Q’s about sizing or fit? Email us at hello@negativeunderwear.com

- Toni S.Verified BuyerSize Purchased 4How it Fits True to SizeAge Range 45 - 54Bra Size 36BYesterdaySize Purchased 4How it Fits True to SizeAge Range 45 - 54Bra Size 36BReviewingSieve Racerback Bra in SparkRated 5 out of 5 starsLove this!
Fits well, sparkles are sexy and understated but very alluring. Bra is practical and supportive at same time!
Was this helpful? - Heather G.Verified BuyerSize Purchased 5How it Fits True to SizeAge Range 45 - 54Bra Size 38C5 days agoSize Purchased 5How it Fits True to SizeAge Range 45 - 54Bra Size 38CReviewingSieve Racerback Bra in SparkRated 5 out of 5 starsI'm in love!
I got the Sieve Racerback and Triangle Bras. Size 5.
I'm in my first week with these beauties and so far, I do believe these are the most comfortable and well- fitting bras I have ever owned. I can't wait to try them out a bit more. See how they hold up with delicate washing over time. And will likely be budgeting to grow my Negative Underwear collection.
Was this helpful? - mVerified BuyerSize Purchased 2How it Fits True to SizeAge Range 25 - 34Bra Size 32C5 days agoSize Purchased 2How it Fits True to SizeAge Range 25 - 34Bra Size 32CReviewingSieve Racerback Bra in BuffRated 3 out of 5 starsNegative starting to cut corners.
I've been purchasing from negative underwear for a few years now. I wear either a thong, bra, top, cardi from them every day of the week. However, as the company grows, I'm a little afraid that they are starting to cut corners on fabric and design aka the luxuries that push the prices so high. I very much hope I'm wrong. But to the review:
Have you ever just not been able to find that one item that would tie your closet or outfit together, but your know it must be out there?
I have been a huge hunt for triange raceback bras in response to this existential question : what do you wear under raceback tanks (ie Citizens of Humanity) if you are trying to not go for a the "headlights are on" look that day (perhaps because ya know, the office), don't want to deal with sticky boobs, and don't want a raceback sports bra sticking out from underneath!?" Seriously, no one on the internet knows. THAT SAID, after trying on this bra, it does seem to be the best option... barely though. Here is an overly thorough review from a girl who just has a dream that one day she will wear a tank top with an invisible bra under it.
CONS
1. Using the Isabel Citizens of Humanity tank as an example, the edges still peak out through the arms holes. Isn't the purpose of the construction of this bra to be a little less visible? Could a version possibly be made with just a little less fabric on the triagles, at least on the sides facing outwards to provide a little more privacy.
2. In addition, the top of…
Was this helpful? - Elizabeth B.Verified BuyerSize Purchased 2How it Fits True to SizeAge Range 45 - 54Bra Size 34D6 days agoSize Purchased 2How it Fits True to SizeAge Range 45 - 54Bra Size 34DReviewingSieve Racerback Bra in BlackRated 5 out of 5 starsSimple and Sexy
Very simple, beautiful, sexy, and surprisingly supportive.
Was this helpful? - Allana D.Verified BuyerSize Purchased 1How it Fits True to SizeAge Range 35 - 44Bra Size 30D1 week agoSize Purchased 1How it Fits True to SizeAge Range 35 - 44Bra Size 30DReviewingSieve Racerback Bra in BlackRated 5 out of 5 starsLove
Fit perfect. Love this bra.
Was this helpful?