Period / Incontinence Pants - Classic Bikini

Flux's classic bikini period underwear combines style with function. Holding up to four tampons' worth, they are a dream to wear day and night and can be worn leak-free for up to 12 hours! They're perfect for any period-haver, or anyone suffering from incontinence or bladder-control issues, as they can be worn no matter your flow for leak-free confidence.

For Periods, Leaks and Incontinence
Holds Four Tampons' Worth / 20-25ml
Wear For Up To 12 Hours Leak-Free
Soft, Stretchy and Comfortable
Lightweight and Quick-drying
OEKO-Tex Certified Materials
Free From Toxins, Chemicals and PFAS/PFOA
Each pair of Flux period pants replace 200+ disposables from going to landfill

Sizing: Swipe through the images to see Flux's size guide, with waist and hip measurements in centimetres. We currently have sizes XXS-2XL (UK 4-6 to UK 20-22) available, which covers UK 8-16/18. However, we are hoping to increase our size, flow and style range in the future. Let us know if you'd like us to stock something else at hello@youunderwear.com!

Materials: Body: 95% TENCEL Modal, 5% Elastane, Gusset: Absorbent Blend, Breathable PUL and Packaging: 100% Recycled and Recyclable Cardboard

Garment Care: Rinse after use, Machine wash on 30-40 degrees, Hang to dry or dry indoors on a radiator. Do not use fabric softener or bleach. No tumble drying.

View our sizing charts below. If you're in-between sizes, we recommend sizing up for comfort! If you need more specific sizing help, please email us at help@youunderwear.com.

Bralette / More supportive bra / Women's knickers / Men's trunks / Girls' bralettes / Girls' knickers / Loungewear

How to Measure Yourself

Chest band: wrap the tape measure around your body, just under your bust.

Bust: measure the fullest part of your bust.

Waist: measure around your body approximately 5cm below your natural waist where the waistband of trousers normally sit.

Lower hip: wrap the tape measure around the fullest part of your hips and bottom.

Two-Way Strap Bralette:

Bralette Size	UK	Band Width (in)	Band Width (cm)	Fits Bra Sizes (Approx)
XS	8-10	27"	68.5	30 B/C/D - 32 A/B/C
S	10-12	29.5"	75	32 B/C/D - 34 A/B/C
M	12-14	32"	81	34 C/D - 36 A/B/C
L	14-16	34.5"	87.5	36 C/D - 38 A/B

More Supportive Bra:

Bra size	Chest band measurement (inches)	Approx. cup sizes	Approx. UK dress size
Small	28-30"	B, C, D	8- 10
Small +	28-30"	DD, E, F	8- 10
Medium	32-34"	B, C, D	12-14
Medium +	32-34"	DD, E, F	12-14
Large	36-38"	B, C, D	16-18
Large +	36-38"	DD, E, F	16-18
Extra large	40-42"	B, C, D	20-22
Extra large +	40-42"	DD, E, F	20-22

Women's Thongs, Bikinis, and Boy Shorts:

UK Sizes	EU Size	Waist (in)	Waist (cm)	Hips (in)	Hips (cm)
6	34	23-24	58.5 - 61	33	84
8	36	25-26	63.5 - 66	35	89
10	38	27-28	68.5 - 71	37	94
12	40	29-30	73.5 - 76	39	99
14	42	31-32	78.5 - 81	41	104
16	44	33-34	83.5 - 86	43	109
18	46	35-36	88.5 - 91	45	114
20	48	37-38	93.5 - 96	47	119
22	50	39-40	99.5 - 101	49	124

Men's Trunks:

Size	Waist (in)	Waist (cm)	Clothing Size (approx.) (in)	Clothing Size (approx.) (cm)
XS	29-31"	74-79	28-30"	71-76
S	31-33"	79-84	30-32"	76-84
M	33-35"	84-89	32-34"	84-89
L	36-38"	91-97	34-386"	91-97
XL	39-41"	99-104	36-38	91-97
XXL	41-43"	104-109	38-40"	97-109
3XL	43-45"	109-114	40-42"	109-114

Girls' Bralettes:

We feel that there isn’t a set size for bodies at different ages, and we don’t want to put any additional pressure on young girls, so our sizing looks a little different. We have 4 sizes, all named after Ugandan towns! We suggest using band width as a starting point, although do get in touch if you have any specific sizing questions.

Size	Band Width (in)	Band Width (cm)	Fits Ages (Approx.)	Worn By:
Jinja	23	57-58	9-10	Hollie & Amelia, age 9 1/2, band with 23"
Kira	25	63-64	10-11	Help us fill this in ...
Lira	27	68-69	11-14	Liv, age 11. Phoebe & Flora, age 11 1/2. Lana, age 13 1/2, 69cm band width, wears 30B/XS. Beth, age 14.
Masaka	29	73-74	13+	Hannah, 32C

Girls’ Knickers:

Details	Waist (in)	Hips (in)	Ages (Approx.)	Women's equivalent size
Jinja	22-23.5”	25-27”	7-9	4 (EU 32)
Kira	24-25”	30-32”	9-11	6 (EU 34)
Lira	25.5-27”	34-35”	11-13	8 (EU 36)
Masaka	27.5-28.5”	37.5-38.5”	13+	10 (EU 38)

Pyjama bottoms:

Our PJs are designed to be unisex, so the sizing is a bit more flexible with an elasticated waist, cord drawstring and also longer leg length.

Details	Women's sizing (UK)	Men's sizing
XS	6-8-10	28-30" waist
S	10-12-14	30-32” waist
M	14-16-18	34-36” waist
L	18-20-22	38-40" waist

- Stretch-blend organic cotton
- 95% GOTS Certified organic cotton, 5% elastane
- Pre-washed, shrink-resistant fabric

Machine wash, do not tumble dry - we suggest the eco-conscious choice of 30°C.

£2.25 for single items, £3.95 for sets and packs

Free shipping on UK orders over £60
All items posted Royal Mail's Tracked 48 service
International Shipping information is available here

We offer a happiness guaranteed return policy. If you are unhappy for any reason, we offer a fuss-free exchange or refund on all unworn and unwashed items within 30 days of purchase.

Orders over £60 qualify for free UK delivery

Fuss-free exchange or refund on all items within 30 days of purchase

Most wonderful underwear & a beautiful business model

Gorgeous underwear that combines comfort and beauty with such a serious commitment to environmental sustainability and social progress. YOU Underwear is stunning to look at and soft to wear, and the company’s business model turns individual consumers into active members of a global community, just like that, with even the smallest purchase. It gives one real hope.

Wow Mary, what an amazing review, you've made my day (& more!). Thank you so much for your amazing support and to hear these kind words about what we're trying to do really means a lot. Thanks for taking the time to get in touch and thanks again. Sx

Period / Incontinence Pants - Classic Bikini - Heavy Flow

Customer Reviews