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D2C SIOC Shoes Make Sustainable Statement

Micah Heftman hadn’t heard the acronym SIOC (ships in own container) when he designed a shoebox for his footwear. He just wanted to avoid a ‘box within a box’ experience. Only when he heard about SIOC did he realize there was a name for his pack design.

Kengos shoes’ most visually striking design element stems from the whip-stitching that mechanically attaches the sole to the upper without adhesive. That design element is reinforced in the packaging design, which is also entirely mechanical.
Kengos shoes’ most visually striking design element stems from the whip-stitching that mechanically attaches the sole to the upper without adhesive. That design element is reinforced in the packaging design, which is also entirely mechanical.

Sustainable footwear startup Kengos kicked off its e-commerce journey as soon as it first hung out a shingle in early 2021. There are a few others in the marketplace already, including entries from heavy hitters Nike and Adidas—Space Hippie and Parley, respectively—and a challenger brand in All Birds. But partners Dave Costello, CEO and Founder, and Micah Heftman, Chief Product Officer, say Kengo’s has a unique niche in the market identified.

“How could the market need another sustainable shoe brand?” Heftman asked the audience at Smithers’ E-Pack event in Chicago in November 2021. “Kengos exists to be a force for good in the fight against climate change, and we do that by producing the world’s most sustainable shoe. We chose footwear as our first product because it’s globally ubiquitous and it’s personally expressive—everyone has shoes, and everyone wants more shoes. The dirty secret in the industry is that it’s a wasteful and resource-intensive product to produce, and if we could just produce them in a more sustainable way we could have a huge impact since there are so many of them produced.”

This upstart challenger brand without a doubt has an interesting product and a unique entry into this market. A visit to the website will explain why in more detail, but the big picture is that the shoes are made from plants and can be considered vegan, using no animal products. They are mechanically held together with no glue or other adhesive, and only use five discrete components compared to the industry average of 30 to 50 components.

But my packaging-trained ears really perked up when I heard Heftman mention the amount of greenhouse gasses produced by the footwear industry, and how he believes that truly sustainable footwear requires drastic changes to existing supply chains and packaging norms. 

And that’s where Kengos’ unique SIOC (ships in own container) e-commerce story began to unfold. Ultimately, Heftman and Kengos decided that if Kengos was going to disrupt the shoe market with a commitment to sustainability, it’d have to walk the walk with its packaging.

Packaging follows the product’s ‘North Star’

According to Heftman, the driving force for the entire Kengos concept was to follow two North Stars: “One is to use the fewest varieties and lowest volume of materials possible; to take away as much as we possibly could while still giving someone a shoe that’s incredible and comfortable and wearable,” he says. “And the second one is, of the remaining materials that we do have to use, make the highest percentage possible of materials used plant-based. Those two North Stars are what created the shoe, so when I went to create the packaging, we applied the exact same two driving forces.

“After all, I only make two things, I make shoes and I make shoeboxes,” Heftman says. “I’m a D2C e-comm brand; there are no other touch points. I have to have my packaging be just as good as my shoes. The package is the product. The shoes are more complex to manufacture than is the shoebox, but the shoebox is just as important.” The corrugated SIOC shipper is printed in three colors on both sides, so all branding and messaging space is used as a billboard.The corrugated SIOC shipper is printed in three colors on both sides, so all branding and messaging space is used as a billboard.

In a brief describing his vision for a shoebox, a memorable unboxing was identified as a key, as it can reinforce the brand for weeks or months in the customers’ mind. The shoebox would also have to serve as billboard space; other than the website, the shoebox is the only physical space that Kengos has for branding. He needed all surfaces doing branding work. Further demonstrating that the packaging is the product, the shoe doesn’t have any glue or adhesive, so the kraft corrugated shoebox couldn’t either. The same applied to size; since the shoes were as minimalistic as possible, the shoebox had to use as little material as possible. And finally, Heftman early recognized the inherent wastefulness of shipping “a box within a box.” All those factors combined to shine a spotlight on SIOC as the answer.

SIOC shoebox

Rather than turning to packaging professionals, Heftman relied on his own shoe business supply chain experience to develop shoebox that he says, like the shoes, are completely unique to the industry. The boxes lock together mechanically—a physical attribute extended from the mechanically stitched shoes themselves—and all available corrugated space is printed for branding and consumer engagement. He initially landed on 180 GSM weight corrugated with fluting between two layers of cardstock. After first experimenting with a lighter gauge, he realized the D2C channel needed to be more robust. And since that first round of kraft corrugated shoeboxes, Kengos continue to iterate smaller.

“Over the course of very early development, I was doing a little bit of shipping internationally to test out the box and I was getting a lot of broken boxes,” Heftman says. “I’d gotten to 180 GPM, and now my next box is an even a heavier weight, it’s the next step up from that. That thing is bulletproof. It uses three-tab mechanical construction instead of two. We’re just making it smaller and smaller, and more robust.”

Kengos shoes span 12 unisex sizes, and two shoebox sizes cover the whole range—one size for the largest shoes, the other for the smallest. Heftman says that in a perfect world, where he’s able to fully follow that reduced material North Star, he might have six different shoebox sizes, with each optimized to fit only two shoe sizes within millimeters. That would keep material usage at a minimum. But with packaging suppliers needing to tool up for each specific shoebox size, and with MOQs being too high for a single shoebox to work only for, say, sizes 6 and 7, that level of optimization isn’t yet practical. Two shoeboxes for a range of 12, though, was doable, and a good material reduction compromise for now. As the business grows and Heftman’s better able to justify MOQs and paying for tooling, look for Kengos to have six shoebox sizes for his 12 shoe sizes.

He points out that this creates wins across COGS (cost of goods sold), since: “less material is always cheaper,” he says. “Less material consumption, less volume, and lower dimensional weight is going to lead to cascading bottom-line wins. You consume lest material, in transit and in storage, you save on last-mile shipping, on labeling, on trim, on collateral, on all of these things that are the status quo [in the footwear industry]. But you don’t need any of that.”

All Kengos uses when it comes to labels is a UPC label since cost-effectively printing a barcode onto the corrugated has been elusive. Also, a ground shipping label is affixed by UPS in a designated window that’s printed onto the corrugated. This makes shipping label placement mindless for whoever is doing the applying, and the brand knows that placement will be repeatable, never covering any design assets.

Kengos shoes are hand-crafted by an artisan finished goods manufacturer in the North American hub for footwear manufacturing and its attendant shoeboxes: Leon, Mexico. These bulk shoes are bulk cartoned, and sent “down the street” to be hand-boxed in the SIOC shoeboxes for individual orders. 

“And even my bulk packaging gets customized,” Heftman says. “I customized the last-mile box, but if I can customize the bulk shippers that the shoes ship in from the finished goods manufacturer, to the warehouse, I can optimize even further, and ensure that 100 percent of the internal volume of the larger cartons are used. I can ensure that the footprint of the pallet is being completely filled, and I can ensure that the maximum shipping height is being utilized. This way we can generate wins across the board.”

Industry standard bulk cartons for finished footwear usually contain 12-18 pairs of shoes. Heftman gets between 24 and 32 of his shoes into his customized bulk cartons.

Tactile tear strip experience

Kengos shoeboxes use a built-in tear strip that consumers use to open the boxes, and people say they remember this unboxing experience because of this satisfying, controlled rip it produces. A tear strip, printed to reference to the product’s stitched design, gives consumers a satisfying, controlled rip when opening the shoebox.A tear strip, printed to reference to the product’s stitched design, gives consumers a satisfying, controlled rip when opening the shoebox.

“It’s a little journey that [consumers] go on that reveals unexpected messaging underneath. Then, they arrive at the shoes themselves, which are in 100% cotton shoe bags, complete with 100 percent cotton closures rope,” Heftman says. “It’s the little touches that are so important.”

Speaking of little touches, a few other details on the box help create a full story that connects the features of the product to the shoebox. The visible, one-knot construction that adjoins the sole to the upper body of the shoe is integral to the brand’s entire aesthetic, so Kengos reinforces the same visual on the tear strip by printing it with the shoe’s characteristic whip-stitch closure stitching. Branding and creative design agency The Working Assembly out of New York City assisted with brand design elements such as these.

Despite all the special touches and thought behind the SIOC pack, Heftman realizes that once the unboxing is complete, that packaging will be headed out with the recycling almost immediately. So it’s during that unboxing that he seeks to make a big impression. Between the shoes and the box, he added a branded, reusable cotton shoe bag that can be repurposed, thus live on longer than the soon-to-be-discarded corrugated.


Watch video   

Brent Lindberg of Fuseneo, a Chicago agency specializing in e-comm, SIOC, and package design testing for D2C, created a nifty unboxing video with the SIOC Kengos shoebox. Click here to check it out.


The time of the unboxing is also the time when consumers are most likely to share information on their purchase on social media. That’s why the three-color screen-printed corrugated prompts consumers on how to correctly @ and # (‘at’ and ‘hashtag’) the brand on Instagram, or whatever the latest social media site might be.

“There’s a call to action,” he says. “Share, tag us, etc. This leads to lots of engagement on social media.”

Unique challenges of SIOC

As pumped as Heftman is about his unique shoeboxes, he recognizes that SIOC is not without challenges. Since these corrugated boxes are designed to be single-use, that makes return logistics more difficult. If a consumer wants a different color or size shoe and needs to make a return, he or she is likely able to re-close the existing shoebox and shoes with overtape. However, that means an entirely new single-use SIOC shoebox will be required to send the new shoes. Kengos Pw 4

Also, since Kengos decided to go the custom route, that means that printing plates and knives for cutting the corrugated had to be created from scratch by his suppliers. There’s certainly some tooling involved if a D2C retailer decides not buy off-the-shelf packaging, and frankly there aren’t a lot of options that are available off-the-shelf at the moment.

“SIOC is also great for single item orders, but not for multi-item orders,” Heftman says. “What I end up having to do is going to the status quo and overboxing it. I don’t have a current solution on how I take two pairs of shoes, in a two-pair order, without overboxing.”

Speaking over overboxing, the entire idea is to avoid overboxing altogether, meaning the single remaining box needs to be that much more durable and robust—it won’t have the assistance of another internal box to help it withstand the rigors of the many-touch e-comm channel. Corrugated used for SIOC needs to be more robust than a shoebox sent to retail, and that costs more and uses more materials.

“And finally, these boxes lock mechanically, so once they’re locked, they’re locked,” he says. “Once they’re locked in the warehouse, I can’t check the contents or add collateral. And if I do, I’d destroy the existing shoebox and need to then invest in a new one. … That said, until now, even though there are improvements that I’ll make and things I need to figure out with SIOC on the whole, it’s been well-worth it from a branding perspective and bottom line,” Heftman concludes.

Consumer reaction makes it worthwhile

Kengo’s customer interviews reinforce Heftman’s belief and reflect that the SIOC packaging hits its mark. These reports indicate that the brand’s larger sustainability goal is well-reflected and recognized in the corrugated, with people noticing that there’s no “box in a box.” Also, the stuffing, dunnage, or product dividers that people are used to seeing in a shoebox are conspicuously absent, and the customer immediately understands why such things aren’t used.

People also report that it’s fun packaging, both in its brightly colored appearance and in its engaging, tactile tear strip.

“I love tearing the box open to reveal the prize inside,” reported one Kengos customer in the research. This comment, above all others, validated Heftman’s original goal of creating a SIOC shoebox that would act like a treasure chest, with consumers eagerly engaging with the corrugated to reveal a treasure inside—and who knows, maybe even post about that treasure on Instagram? PW

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The largest PACK EXPO East in history is March 18-20 in Philadelphia! In one convenient location, you’ll discover new technology from top suppliers, get quality problem-solving time with experts and learn the latest trends in free educational sessions.
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Discover innovations from 400+ packaging & processing suppliers.