Black Onyx Set: Plunge Backless Bra & Flirt French Knickers
InvisiBra Size A fits UK 26AA, 26A, 26B, 28AA, 28A, 28B, 30AA, 30A, 30B, 32AA, 32A, 34AA, 34A, 36AA, 38AA. Between sizes? Go down one.
In stock. Order by 12pm, Monday to Friday, for next-day delivery.
This order gets free UK delivery.
Secure checkout. Questions? Message us.
The Black Onyx U-plunge bra with the Flirt Frenchie knickers. Made for a deep neckline and a black dress.
What's in the set
- Black Onyx U-plunge backless bra — cut low for a deep neckline.
- Flirt Frenchie black lace French knickers — black lace.
You'll also find this bra in our plunge backless bras, push-up backless bras and black backless bras collections.
Want an extra boost? Slip in our push-up bra inserts.
Sizing
The bra comes in InvisiBra Size A, InvisiBra Size B, InvisiBra Size C and InvisiBra Size D. InvisiBra sizes aren't the same as your usual bra size, so find yours in 30 seconds with our size guide. Between sizes? Go down one.
Pick your knicker size separately, the way you normally would.
Care
Wash the cups after every wear in lukewarm water with a little mild soap, rinse them with the palm of your hand and leave them to air dry sticky side up. Never use your fingernails, a brush or a towel on the adhesive. All the care steps.
Get it by
- Next day £12.68 · order by 12pm, Mon to Fri
- Next working day
- Tracked 24 £6.98
- 2–3 working days
- Tracked 48 £4.98, free over £40
- 3–5 working days
Dates count working days and skip bank holidays. We deliver to Europe and further afield too. You'll see the options and prices at checkout.
Arrived faulty? Email customerservice@invisibra.co.uk with photos as soon as you spot it and we'll sort it out. Our Returns policy has the details.
Your questions, answered
Will it stay on all night?
Yes. Apply it to clean, dry skin and InvisiBra stays put all day and all night, through a full dance floor session or a humid summer wedding. It stays on until you decide to take it off.
Is it sweat-proof?
Yes! The adhesive is designed to handle sweat, body heat and movement, so you can wear it on holiday, at a festival or in a packed club.
Does it work for bigger boobs?
It can, if your bust is firm. Check the fuller-bust guide on our size guide to see whether InvisiBra will work for your size.
How many times can I wear it?
With proper care, 30+ wears. Clean the cups after every wear: lukewarm water, a little mild soap, and gently rub the sticky side with the palm of your hand. Then let them air dry. That refreshes the adhesive, so it stays sticky wear after wear.
Can I return it?
Bras sit right against your skin, so for hygiene reasons all sales are final. We can't take a bra back because it's the wrong size or you've changed your mind, so check our size guide or message us before you order. If anything arrives faulty, we'll sort it out.
Find your InvisiBra size
This style comes in InvisiBra Size A, B, C and D.
Find your usual bra size: your band down the side, your cup along the top. The square where they meet is your InvisiBra size. Swipe the chart sideways for bigger cups.
| Your usual cup size | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Band | AA | A | B | C | D | DD | E | F | FF | G | GG |
| 26 | InvisiBra Size A | InvisiBra Size A | InvisiBra Size A | InvisiBra Size B | InvisiBra Size B | InvisiBra Size B/C, between sizes: go down one | InvisiBra Size C | InvisiBra Size C | InvisiBra Size D | InvisiBra Size E | InvisiBra Size F |
| 28 | InvisiBra Size A | InvisiBra Size A | InvisiBra Size A | InvisiBra Size B | InvisiBra Size B | InvisiBra Size C | InvisiBra Size C | InvisiBra Size D | InvisiBra Size D/E, between sizes: go down one | InvisiBra Size E | InvisiBra Size F |
| 30 | InvisiBra Size A | InvisiBra Size A | InvisiBra Size A | InvisiBra Size B | InvisiBra Size B | InvisiBra Size C | InvisiBra Size C | InvisiBra Size D | InvisiBra Size E | InvisiBra Size F | No recommendation, message us |
| 32 | InvisiBra Size A | InvisiBra Size A | InvisiBra Size B | InvisiBra Size B | InvisiBra Size C | InvisiBra Size C | InvisiBra Size D | InvisiBra Size E | InvisiBra Size F, lifting styles only | InvisiBra Size F, lifting styles only | No recommendation, message us |
| 34 | InvisiBra Size A | InvisiBra Size A | InvisiBra Size B | InvisiBra Size C | InvisiBra Size D | InvisiBra Size D | InvisiBra Size E | InvisiBra Size F, lifting styles only | InvisiBra Size F, lifting styles only | No recommendation, message us | No recommendation, message us |
| 36 | InvisiBra Size A | InvisiBra Size B | InvisiBra Size C | InvisiBra Size D | InvisiBra Size D | InvisiBra Size E | InvisiBra Size F, lifting styles only | InvisiBra Size F, lifting styles only | No recommendation, message us | No recommendation, message us | No recommendation, message us |
| 38 | InvisiBra Size A | InvisiBra Size B | InvisiBra Size C | InvisiBra Size D | InvisiBra Size E | InvisiBra Size F, lifting styles only | InvisiBra Size F, lifting styles only | No recommendation, message us | No recommendation, message us | No recommendation, message us | No recommendation, message us |
| 40 | InvisiBra Size B | InvisiBra Size C | InvisiBra Size D | InvisiBra Size E | InvisiBra Size F | InvisiBra Size F, lifting styles only | No recommendation, message us | No recommendation, message us | No recommendation, message us | No recommendation, message us | No recommendation, message us |
- – No size we'd recommend: message us
- Fuller bust: lifting styles only
- Two letters: you're between sizes, so go down one. Styles that come in Size DD: pick that for D/E.
Faded sizes aren't available in this style.
Between sizes or not sure? Go down one. InvisiBra works best snug or slightly small. Wearing something tight or low-cut? Stick to your size.
Don't know your bra size? Work it out with our 4-step calculator. Usually wear a DD cup or bigger? Read the fuller-bust guide first.