First Period Kit
The perfect kit to get your teen ready for their first period. Everything they need for their lightest days and heaviest nights.
What You Get:
3 Light Leakproof No-Show Underwear*
- Each pair absorbs about 1 regular tampons worth of blood, sweat or discharge.
3 Super Leakproof™ No-Show Underwear*
- Each pair absorbs about the same as 1.5 regular pads’ worth of blood.
1 Super Sleepover Short
- Absorbs about the same as 2.5 regular pads’ worth of blood.
1 Reusable Pouch
*In your choice of Bikini, or Boyshort.
The perfect kit to get your teen ready for their first period. Everything they need for their lightest days and heaviest nights.
What You Get:
3 Light Leakproof No-Show Underwear*
- Each pair absorbs about 1 regular tampons worth of blood, sweat or discharge.
3 Super Leakproof™ No-Show Underwear*
- Each pair absorbs about the same as 1.5 regular pads’ worth of blood.
1 Super Sleepover Short
- Absorbs about the same as 2.5 regular pads’ worth of blood.
1 Reusable Pouch
*In your choice of Bikini, or Boyshort.
UltraThin Leakproof Underwear
Machine wash cold, do not bleach, do not iron, do not dry clean, lay flat to dry.
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
Super Leakproof Underwear
Body: 70% Nylon, 30% Spandex
Lining: 84% Modal, 8% Seaweed, 8% Spandex
Gusset: Leakproof Technology®, 100% Polyester, Polyurethane Film
Machine wash cold and tumble dry on low. Do not bleach, iron, or dry clean.
Super Sleepover Short
Body: 70% Nylon, 30% Spandex
Lining: 84% Modal, 8% Seaweed, 8% Spandex
Gusset: Leakproof Technology®, 100% Polyester, Polyurethane Film
Machine wash cold and tumble dry on low. Do not bleach, iron, or dry clean.
For additional product ingredient information click here.
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.
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.