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SuperPlus Leakproof® No-Show Boybrief
SuperPlus Leakproof® No-Show Boybrief
$39.00
USD
Buy 3+ Save 15%, Buy 5+ Save 20%
Absorbs 7-11 super tampons
Front-to-back liner
Bonded seams prevent leaks
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.
Build Your 3-Pack
SuperPlus Leakproof® No-Show Boybrief
SuperPlus Leakproof® No-Show Boybrief
SuperPlus Leakproof® No-Show Boybrief
Rewards Members Earn
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Product Description
Comfort-First Fit
Ultimate Leakproof Protection
Day & Night Comfort
Machine Washable
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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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PATENTED LEAKPROOF TECHNOLOGY
Our longest, most absorbent liner—ever.
Our original Fresh Fix Technology® features a built-in absorbent liner that soaks up about 7–11 super tampons’ worth of liquid—so you stay fresh, comfortable, and in control.
Soft Top Layer
Middle Layer
Leakproof Layer
Bottom Layer
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How to wash
Knix underwear is 100% reusable and machine washable, just like your regular undies.
Not required. But for best results, you can rinse your leakproof with cold water in the tub or sink before washing.
Machine wash on a cold, gentle cycle with mild detergent.
For their longest life, air drying is best. Hang or lay flat to dry.
Fabric softeners, bleach, ironing, or heat from the dryer.
What our customers are saying
Generated by AI from 53 most recent customer reviews
Last updated 4 months ago
Customers say these boybrief underwear provide excellent overnight protection with front-to-back coverage that prevents leaks. Many appreciate the soft, comfortable fabric and full coverage design. Users find them particularly effective for heavy flow days and overnight use, with some noting they can wear them for 12+ hours without issues. Several mention the sizing runs large and recommend sizing down for a better fit. While most praise the comfort and protection, some find the waistband too tight or the leg openings too loose. A few users note the absorbent pad feels thick or bulky compared to other styles. The extended coverage from front to back is frequently highlighted as a key benefit for preventing nighttime leakage.
80%would recommend this product
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114 reviews
- Rated 5 out of 5 starsYesterdayLove!!
I absolutely love the feel and comfort of Knox! They are definitely super plus leak proof! I’m already placing another order!
NJNadia J.Verified BuyerReviewingSuperPlus Leakproof® No-Show Boybrief - Rated 5 out of 5 stars2 days agoTakes all worries away!
These are so comfortable and I loooove not having to worry about any leaks! These are for sure a game changer. Will be buying more
ASAmanda S.Verified BuyerReviewingSuperPlus Leakproof® No-Show Boybrief - Rated 5 out of 5 stars5 days agoGame changer!
A friend recommended these to me and I don't know how I can go back to my old ways - they work so well! I've used them on both heavy and light days and they've lasted through the work day with no leaks, through workouts, and overnight. They are comfortable and I *almost* forget I'm on my period.
LSLaxmi S.Verified BuyerReviewingSuperPlus Leakproof® No-Show Boybrief - Rated 5 out of 5 stars6 days agoBirthday traffic nightmare? These SuperPlus Leakproof Boybriefs were the real MVP
Saturday was my birthday and we were heading to Niagara for a fun trip… until a big accident turned the highway into an 8-hour parking lot. On top of that, it was the first (and heaviest) day of my period the kind of flow that normally has me changing every couple hours.
I was honestly dreading the whole situation, but these SuperPlus Leakproof No-Show Boybriefs completely saved me. I wore them the entire 8 hours stuck in traffic and never once leaked or felt uncomfortable. No constant worrying, no awkward stops, just peace of mind when I needed it most.
They stayed in place, felt soft and secure, and handled my heaviest flow like it was nothing. I’m so impressed — these are officially my new period-day essential. Thank you for making a stressful birthday traffic jam a whole lot more manageable!
MGMeri G.Verified BuyerReviewingSuperPlus Leakproof® No-Show Boybrief - Rated 4 out of 5 stars2 weeks agoReview boy brief
I would rather have Basic low rise pantie style, instead of the boy brief! They are too confining, but they do the trick..
MUMargaret U.Verified BuyerReviewingSuperPlus Leakproof® No-Show Boybrief - Rated 4 out of 5 stars2 weeks agoLike the style
I bought two of these same style underwear and one of them fit me perfectly and the other one was a little tight. They’re both the same size and style.
JSJeff S.Verified BuyerReviewingSuperPlus Leakproof® No-Show Boybrief - Rated 5 out of 5 stars3 weeks agoExcellent Product
These SuperPlus Leakproof No-Show Boybrief are an excellent choice. As a 71 year old lady I appreciate the comfort they rpovide.
LMLinda M.Verified BuyerReviewingSuperPlus Leakproof® No-Show Boybrief - Rated 5 out of 5 stars3 weeks agoLove
These are the best
CGChelsie G.Verified BuyerReviewingSuperPlus Leakproof® No-Show Boybrief - Rated 5 out of 5 stars4 weeks agoNo- show boybrief
Very pleased, comfortable and effective.
EAElizabeth A.Verified BuyerReviewingSuperPlus Leakproof® No-Show Boybrief - Rated 5 out of 5 stars4 weeks agoNever got better
My period protection is best it’s ever been. Thank you Knix!
IFIsabel F.Verified BuyerReviewingSuperPlus Leakproof® No-Show Boybrief - Rated 5 out of 5 stars1 month agoBoybrief
I love them
EEElaine E.Verified BuyerReviewingSuperPlus Leakproof® No-Show Boybrief - Rated 5 out of 5 stars1 month agoGreat fit, comfortable
Have bladder cancer, does an great job , no spotting on pants!
SCStuart C.Verified BuyerReviewingSuperPlus Leakproof® No-Show Boybrief
