Boxer Trial Pack - Flat Seams

This listing is for the Find My Size WunderUndies Boxers Trial Pack with flat seams.

We have found that while kids love their WunderUndies, they are very particular about their sizing. Some like them looser and some like them tighter. So the Find My Size Trial Pack was invented! With this trial pack you will receive 2 pairs of WunderUndies boxers in 2 different sizes. This way you can find the size that suits your child the best. 

WunderUndies boxers are thoughtfully designed children’s underwear, perfect for kids with sensory sensitivities who hate underwear. Made from luxuriously soft, eco-friendly bamboo and cotton blend fabric, they offer unparalleled comfort while being kind to the planet. These undies are entirely elastic-free, featuring a fabric waistband that sits snugly and securely without causing irritation—so no slipping, just the perfect fit.

What sets our flat seam style WunderUndies apart is their flat-seam construction, created with precision using a flat lock machine. Seams on the waistband are positioned on the outside and sewn flat, ensuring a smooth feel against your child’s skin. Combined with their tagless design, these boxers redefine comfort for sensitive kiddos.

Once your little one experiences WunderUndies, they’ll never want to wear anything else—and we’re confident you’ll feel the same.

Available in sizes 2T–12.

With WunderUndies first round of boxers, it quickly became clear that they ran small. So with the next round we made some needed changes. They are:
1. We shifted everything one size. Our old size 12s are now size 10s and so on and so forth.
2. We enlarged the waistbands ever so slightly. 

If you have bought from us before and are worried about what size might fit your child now, you are welcome to get another trial pack. But if you are new to WunderUndies we believe that the size chart above now more accurately reflects the best fit for our Flat Seam undies. If you are buying Soft Seam Undies, consider sizing up. 

As always, we highly recommend getting a trial pack first.

Some people see bamboo fabric and worry that it will be hard to care for. It's not! Many customers have praised the durability of WunderUndies. Here's what you need to know:

Machine wash cold with mild detergent. No fabric softener. Dry on low. If you feel the need to iron your undies, do that on low too. These are the practices for the longest lasting undies.

Our fabric blend of 67% bamboo, 28% cotton, and 5% spandex is crafted to provide unmatched comfort, durability, and versatility. Bamboo offers exceptional softness, breathability, and moisture-wicking properties, making it perfect for sensitive skin and active kids. Cotton adds strength and structure, ensuring long-lasting wear, while the addition of spandex delivers just the right amount of stretch for a snug, flexible fit. This thoughtful combination creates underwear that feels gentle, moves effortlessly, and stands up to everyday play, all while supporting sensory-friendly comfort.