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Home / Boyshort Underwear / Leakproof UltraThin No-Show Boybrief

Leakproof UltraThin No-Show Boybrief

$34.00 CAD

Mix & Match: 3+ for $25 each
Checkmark

Absorbs about 2.5 super tampons

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Invisible under clothes

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Moderate protection without the bulk

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Machine washable

| Black with White Polka Dot
| Black with White Polka Dot
| Black with White Polka Dot
| Black with White Polka Dot

Absorbency: Moderate

Moderate
Drop
Drop
Drop
Drop
Drop
about 2-4 super tampons
Ultra
Drop
Drop
Drop
Drop
Drop
about 7-11 super tampons

Color: Black with White Polka Dot Limited Edition

Size:

True to Size

•

Size:

Size and Fit Guide

Leakproof Underwear is Sales Tax Free in Canada*
Free Express Shipping on orders $125+

Shipping

Shipping

Processing Timelines

Please allow 1-2 business days for our warehouse team to pack and ship your order. During peak periods such as sales, holidays and product launches, please allow up to 4 business days for us to process your order.

Delivery Time

For the most up-to-date delivery time estimates, please refer to the shipping timeline at checkout. Delivery timelines vary depending on location and do not include processing times.

Shipping Charges

Orders over $100* CAD = Free Shipping (2-6 business days)

Orders under $100* CAD = $12 CAD Shipping (1-3 business days)

Orders delivering to NWT, Nunavut and Yukon are subject to $20 delivery fee.

*After discounts, before shipping and taxes.
Easy Exchanges within 30 Days

Returns

Returns

Sale & Last Call

Items discounted 30% and below are eligible for size exchange or store credit. Items discounted above 30% and above are final sale – no refunds, store credits, or exchanges can be accommodated.

Free Returns

Knix covers the return shipping fees for exchanges and refunds initiated through our Return & Exchange Portal. Exchange orders initiated through our Return & Exchange portal are also eligible for free shipping within the USA and Canada. Please note, the shipping fees on your original order are non-refundable.

Return Policy

Return policy varies by product, please check if your item is refund or exchange eligible by viewing our full policy here.
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Comfort-First Fit

Mid-rise boybrief silhouette with full bum coverage for a smooth, comfortable fit.

Worry-Free Protection

Our newest leakproof innovation provides more absorbency without the bulk. Patented 360 LeakSeal™ technology locks in leaks at every edge.

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.

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 regular underwear.

Zoom

| Black with White Polka Dot
| Black with White Polka Dot
| Black with White Polka Dot
| Black with White Polka Dot

How to Choose?

Essential

Drop
Drop
Drop
Drop
Drop
  • • Everyday Wear
  • • No leakproof protection
  • tsp
    0 tsp

Heavy

Drop
Drop
Drop
Drop
Drop
  • • heavy period days
  • • overnight protection
  • • light bladder leaks
  • tsp
    about 8-14 tsp
  • pad
    about 1.5-3 regular pads
  • tampon
    about 4-7 super tampons
  • cup
    about 1.5-3 menstrual cups

Light

Drop
Drop
Drop
Drop
Drop
  • • light period days
  • • sweat
  • • discharge
  • tsp
    about 1-3 tsp
  • pad
    about 1-3 pantyliners
  • tampon
    about 1-3 regular tampons
  • cup
    about 0.5 menstrual cups

Moderate

Drop
Drop
Drop
Drop
Drop
  • • moderate period days
  • • light bladder leaks
  • • sweat
  • tsp
    about 4-8 tsp
  • pad
    about 1-1.5 regular pads
  • tampon
    about 2-4 super tampons
  • cup
    about 0.5-3 menstrual cups

Ultra

Drop
Drop
Drop
Drop
Drop
  • • extra heavy period days
  • • overnight protection
  • • light bladder leaks
  • tsp
    about 15-20 tsp
  • pad
    about 1.5-2.5 super pads
  • tampon
    about 7-11 super tampons
  • cup
    about 2-3 menstrual cups
FRESH FIX TECHNOLOGY®

Built-in protection that feels like nothing at all.

Our patented 360 LeakSeal™ technology locks in leaks at every edge. The ultra-thin liner absorbs about 2.5 super tampons worth of liquid.

Soft Top Layer

Soft Top Layer

Gently wicks away moisture while keeping you feeling fresh and odor-free.

Our Best-Selling Underwear

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4.8
Rated 4.8 out of 5 stars
Based on 72 reviews
Total 5 star reviews: 63 Total 4 star reviews: 5 Total 3 star reviews: 4 Total 2 star reviews: 0 Total 1 star reviews: 0
94%would recommend this product
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72 reviews
  • Rated 5 out of 5 stars
    7 hours ago
    Ultra thin boy brief

    Love it

    Elaine A.
    Verified Buyer
    Was this helpful?
  • Rated 5 out of 5 stars
    2 days ago
    Comfortable and leakproof

    Very comfortable, doesn’t ‘rise up’ on your behind likes sir me other brand.

    Teresa W.
    Verified Buyer
    Was this helpful?
  • Rated 5 out of 5 stars
    6 days ago
    Boybrief stays put all day or night

    I usually order the boy shorts. Tried the boybrief for the first time and it's just as good, no riding up or falling down, stays put all day/night. Fun pattern. I'm an XS and true to size.

    Anna S.
    Verified Buyer
    Was this helpful?
  • Rated 5 out of 5 stars
    1 week ago
    Redesigned?

    I’ve been a Knix customer for years and this tranche of products seems to be redesigned! There seems to be more seams? But the three pair I ordered fit great and I love the new prints. I didn’t notice any problematic panty-lines, and the protection level is great, as always. So far I’m pleased with my latest order!

    Amanda H.
    Verified Buyer
    Was this helpful?
  • Rated 5 out of 5 stars
    1 week ago
    Love these

    These are so good! They feel like nothing on. I'm between a 6 and 8 pant size and the medium is perfect. I can't get over how comfy they are. I will be getting more.

    Jenny
    Verified Buyer
    Was this helpful?
  • Rated 5 out of 5 stars
    1 week ago
    Awesome

    They fit perfectly!

    Sherrie B.
    Verified Buyer
    Was this helpful?
  • Rated 4 out of 5 stars
    1 week ago
    Good fit

    The boy short works great for me.

    There was an issue on the order. I received 2 shorts in the wrong size. They sent (2) XXL instead of the size I ordered.

    Ann G.
    Verified Buyer
    Was this helpful?
  • Rated 5 out of 5 stars
    1 week ago
    Comfortable fit

    I have many different shapes of KNIX underwear and this was surprisingly attractive and comfortable, even for a larger size. I am ordering another exactly the same! I like the feel and the slim profile of the Ultra thin gusset. My new favorite!

    Deborah A.
    Verified Buyer
    Was this helpful?
  • Rated 3 out of 5 stars
    2 weeks ago
    Fair

    Rather have hiphuggers. Boyshorts ride on lega. Don't like high rise armr all or bikini ottoman thing Bring back hiphugger please

    Bonnie H.
    Verified Buyer
    Was this helpful?
  • Rated 5 out of 5 stars
    2 weeks ago
    Boy Shorts!

    Love these. Comfortable and pretty. Boy shorts are my preferred panty and not offered everywhere, especially this comfortable.

    Lisa D.
    Verified Buyer
    Was this helpful?
  • Rated 5 out of 5 stars
    2 weeks ago
    Bot shorts

    I love Knix boy briefs. Comfortable and reassuring.

    Helen W.
    Verified Buyer
    Was this helpful?
  • Rated 5 out of 5 stars
    2 weeks ago
    Fit

    Love the way they fit

    Sherrie B.
    Verified Buyer
    Was this helpful?