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ACOTAR™ Leakproof Ultrathin™ No-Show Bikini Box Set
ACOTAR™ x Knix
ACOTAR™ Leakproof Ultrathin™ No-Show Bikini Box Set
$115.00
CAD
Limited-edition ACOTAR™ x Knix collection
Absorbs about 2.5 super tampons
Invisible under clothes
Moderate protection without the bulk
Machine washable
Size and Fit Guide
How to Measure
In order to select the correct sizing, we recommend you take the following measurements using a soft tape measure. If necessary, ask someone else to help.
Waist
Measure around the narrowest part of your torso, usually just above your belly button. Keep the tape snug and level, but not tight. The number where it meets is your waist measurement.
Hip
Stand with your feet together and measure around the fullest part of your hips and buttocks. Keep the tape level and snug, but not tight. The number where it meets is your hip measurement.
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ACOTAR™ x Knix
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Part of the limited-edition ACOTAR™ x Knix Collection
Comfort-First Fit
Bikini silhouette with a classic mid-rise fit, medium hip and bum coverage.
Moderate Absorbency
Absorbs 2.5 super tampons worth of liquid—perfect for moderate flow days, light bladder leaks, and sweat. The carbon cotton gusset top layer keeps you dry.
Worry-Free Protection
Perfect for moderate period days, light bladder leaks, and sweat. Moisture-wicking liner keeps you dry and comfortable.
No-Show Style
Buttery-soft and smooth fabric gives a seamless look and feel. Disappears under clothes, even leggings.
Easy to Wash
Machine washable, just like your regular underwear.
ACOTAR™ is a trademark of Fireheart Inc. ©2015-2026, Sarah J. Maas.
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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
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Recently Viewed
Reviews Summary
Generated by AI from 100 most recent customer reviews
Last updated 5 months ago
Customers say these period underwear are comfortable and provide effective protection without the bulk of traditional pads. Many appreciate the soft, buttery fabric that feels like regular underwear and the no-show design under clothing. Users frequently mention confidence during workouts, daily activities, and even swimming. Parents often purchase these for teenage daughters who love the comfort and security they provide. Common feedback includes praise for the absorbency and leak-proof performance. However, several reviews mention sizing inconsistencies, with some finding recent purchases run smaller than previous orders. A few customers note the leg holes can feel tight or that the fit varies between different fabric types.
84%would recommend these products
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Usual Pant Size
785 reviews
- Rated 5 out of 5 stars1 week ago5 Stars
So happy to get this, and the box set look it comes in omg the ACOTAR collab is amazing and the product high quality
AAddisonReviewingACOTAR™ Leakproof Ultrathin™ No-Show Bikini Box Set Thorns & Roses/Mist & Fury/Wings & Ruin/Frost & Starlight/Silver Flames / L - Rated 5 out of 5 stars3 minutes agoWill buy again!
My first knix and I’ll be buying more, so comfortable.
MAMorgan A.Verified BuyerReviewingLeakproof UltraThin™ No-Show Bikini 3-Pack - Rated 5 out of 5 stars11 hours agoLove the color
I was in need for some new undies from Knix. The inside lining is different, seems thicker. Love the colours I got and can't wait to try my sleep shorts.
ACAshley C.Verified BuyerReviewingLeakproof UltraThin™ No-Show Bikini 3-Pack Ember Fox/Dark Cherry/Autumn Tapestry / L - Rated 5 out of 5 stars11 hours ago5 Stars
Beautiful and excellent quality
CCaitlinReviewingACOTAR™ Leakproof Ultrathin™ No-Show Bikini Box Set Thorns & Roses/Mist & Fury/Wings & Ruin/Frost & Starlight/Silver Flames / S - Rated 5 out of 5 stars21 hours agoParfaite
Elles sont parfaitement coquettes. Bonne grandeur et vraiment confortables.
MLmyriam l.Verified BuyerReviewingLeakproof UltraThin™ No-Show Bikini 3-Pack Spring Court Bloom/Pink/Thorns and All / XL - Rated 5 out of 5 stars2 days agoDancing Drier
I am well past my period days, but I attend dance class and socials 4-5 nights a week, 2-3 hours a night. Let's just say, things get pretty sweaty down there. My dance pants can be pretty form fitting and, besides the discomfort of wet pants (ew), I didn't want to look like I'd peed my pants. I thought I 'd give your panties a try for dance nights. I loved them so much, I bought a bunch more.
DSDeborah S.Verified BuyerReviewingLeakproof UltraThin No-Show Bikini - Rated 5 out of 5 stars2 days agoGreat product!
Great product!
VEVeronika E.Verified BuyerReviewingLeakproof UltraThin No-Show Bikini Warm Sand / M - Rated 5 out of 5 stars4 days agoGet them! Life changing..
I wish I bought these years before I did. I’ve had 8 pairs on serious repeat for 3 years. I just bought 6 more (acotar night court, yes please!) Hang to dry & they last. Haven’t spent a dollar on landfill liners since these & a cup for heavy days. Think of the money you’ll save! Invest!
LGLanessa G.Verified BuyerReviewingLeakproof UltraThin™ No-Show Bikini 3-Pack Ink That Binds/Midnight/Velaris Night Sky / M - Rated 5 out of 5 stars5 days agoBest Underwear Ever
My entire collection is Knix and i don’t regret it. They make my days more manageable and I feel more confident knowing im protected no matter what.
KFKayla F.Verified BuyerReviewingLeakproof UltraThin™ No-Show Bikini 3-Pack Ember Fox/Dark Cherry/Autumn Tapestry / M - Rated 5 out of 5 stars6 days agoAmazing
Both my teen daughters love these. They are 13 and 15
TMTiffany M.Verified BuyerReviewingLeakproof UltraThin No-Show Bikini - Rated 5 out of 5 stars1 week agoAcotar collection
Absolutely loved this collection and this set was so super comfortable! This was my first set and was so happy with it
ASAlexandria S.Verified BuyerReviewingLeakproof UltraThin™ No-Show Bikini 3-Pack Ink That Binds/Midnight/Velaris Night Sky / M - Rated 5 out of 5 stars1 week ago5 Stars
Not as no-show as I’d like but pretty close and i usually wear looser pants on my period anyway so not the biggest deal. Extremely comfortable and didn’t worry about leaks at all
KKaitlynReviewingLeakproof UltraThin No-Show Bikini Mulberry / M
