Leakproof UltraThin No-Show Underwear 7-Pack - Classic Prep

This 7-pack of period undies period undies provide the ultimate comfort you want, plus ultra-thin protection you need from sweat, discharge and leaks. It’s a classic silhouette made with a super soft-and-stretchy, quick-drying material. It absorbs about the equivalent of 2.5 super tampons for an extra dose of confidence on those medium-flow days.

Key Features:
- 360LeakSeal™ patented technology designed to seal in leaks from every angle
- Soft and stretchy for comfort throughout the day
- Seamless look for any OOTD
- Quick dry for that fresh feel

Your teen’s fave comfy period undies, now in a 4-pack.
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Holds about 2.5 super tampons' worth of blood.
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Rapidly absorbs moisture to keep you fresh and dry.
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Thin, subtle, and designed to feel just like regular underwear.
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Simply care with mild detergent and machine wash on cold.

This 7-pack of period undies period undies provide the ultimate comfort you want, plus ultra-thin protection you need from sweat, discharge and leaks. It’s a classic silhouette made with a super soft-and-stretchy, quick-drying material. It absorbs about the equivalent of 2.5 super tampons for an extra dose of confidence on those medium-flow days.

Key Features:
- 360LeakSeal™ patented technology designed to seal in leaks from every angle
- Soft and stretchy for comfort throughout the day
- Seamless look for any OOTD
- Quick dry for that fresh feel

Leakproof UltraThin Underwear

Body: 77% Nylon, 23% LYCRA® XTRA LIFE™Spandex;

Fresh Fix Technology®Gusset: Gusset 1: 86% Cotton, 10% Spandex, 4% Carbon; Gusset 2: 96% Polyester, 4% Spandex; Gusset 3: 83% Polyester, 11% Spandex, 6% Polyurethane

Machine wash cold with mild detergent, do not bleach, lay flat to dry.

Additional Product Ingredient Information

For items with a 20% or more discount, you may exchange for another item or return for store credit. No refunds can be accommodated. 

Items marked as “Flash Sale” or “Clearance” are final sale, meaning no returns, exchanges or refunds can be accommodated. No exceptions. 

Please note: Sale items are not eligible for our First Pair Risk-Free Policy.


We offer free standard shipping on all orders over $70. We ship our items via DHL or Canada Post depending on your location. Please allow 1-2 business days for your items to be processed and shipped. During high volume periods, your order may take up to 7 business days to dispatch from our warehouse location.


US Orders: Please allow 3–10 business days for orders to arrive.
International Orders: Please allow 10–25 business days for orders to arrive.


NOTE: Orders placed on Friday after 1 PM will not be processed until the following Monday.
CANADIAN CUSTOMERS: Shop www.knixteen.ca to order in Canadian currency.

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Super Absorbency

Absorbs 9–12 tsp (45–60 ml) of blood—that’s about 9–12 regular tampons or pads! Perfect for overnight protection or your heaviest days when changing into a fresh pair might not be convenient.


High Absorbency

Absorbs 4–8 tsp (20–40 ml) of blood, or the equivalent of 4–8 tampons or pads. These are perfect for heavy flow days.


Medium Absorbency

Absorbs up to 3 tsp (15 ml), or about 3 tampons or pads worth of blood. Ideal for light to medium flow days or as backup to tampons or period cups.

All of our period underwear, swimwear, reusable pads, and activewear have our patented leakproof technology built right in.

First Layer: Moisture-wicking, antibacterial technology wicks away sweat and moisture while neutralizing odors to keep you fresh all day long. 

Second Layer: A super thin, highly absorbent liner that holds the power of 3–20 tampons or pads.

Third Layer: A secure, liquid-resistant outer layer keeps leaks from happening.

The short answer: nope! Depending on the absorbency level of your period underwear and the heaviness of your flow, you can wear our period undies on their own or as a backup to tampons or menstrual cups. You can wear our High and Super absorbency underwear alone and be totally protected, while our Medium absorbency underwear can be worn alone on lighter days or as backup on heavier days.

Step 1: Give your underwear a quick rinse under cold water.
Step 2: Throw it in the washing machine with your regular clothes. Wash on cold with mild detergent (no softener or bleach).
Step 3: There are two ways to dry them depending on the undies you have: lay flat to dry for medium absorbency products, or tumble dry on low for high to super absorbency products.
Step 4: That’s it! No ironing needed.

Check out our size chart here. If you want some help, we have virtual fitters ready on deck to help you find your perfect fit. Book a video call with them today.

Because they’re, well, underwear, we can’t accept exchanges or returns on used items. BUT you can try your first pair on your first order risk-free for 30 days!


If you ordered the wrong size of period underwear, we’ll send you a different pair at no cost or offer you a standard refund within 30 days of delivery (excluding original shipping fees).


If your order included multiple period underwear, open, wash, and wear one pair only. That way if you don’t love them, any unopened packages from the same purchase will be eligible for an exchange or standard refund (excluding original shipping fees).


All unopened packages will be donated to local organizations to support people in need.


*All Mystery Bundles are final sale.

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ABSORBENT
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ABSORBENT
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ABSORBENT
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JUST PLAIN BETTER
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REUSABLE
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COMFORTABLE
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ABSORBENT
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JUST PLAIN BETTER
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REUSABLE
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COMFORTABLE
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ABSORBENT
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JUST PLAIN BETTER
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REUSABLE
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COMFORTABLE
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ABSORBENT
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JUST PLAIN BETTER
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REUSABLE
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COMFORTABLE
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ABSORBENT
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JUST PLAIN BETTER
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