New Balance has made a boot that turns into a mule and then into a slipper. Seriously. The Tokyo Design Studio Niobium C1 is one of the stranger shoes we’ve come across lately, but there’s a practical idea behind the $299.99 price tag: instead of bringing different shoes for different parts of a trip, you can change the ones you’re already wearing.

This isn’t a brand-new experiment. New Balance first introduced the Niobium concept in 2020, brought the C1 back in 2026 and added more color options in October. The idea is still pretty wild, though. With its full upper attached, it looks like a chunky, futuristic waterproof boot. Reconfigure it and you’ve got an outdoor mule. Strip it down further and it becomes an indoor slipper.

How does the Niobium C1 actually work?

The trick is in its modular construction. Zippers run down the tongue and around the heel, allowing the different pieces to come together. New Balance uses stretch ripstop fabric, welded polyurethane overlays and a neoprene collar, along with elastic bungee laces you don’t have to tie. Underfoot, there’s EVA foam cushioning and a rubber outsole.

In boot form, an eVent waterproof membrane helps keep water out while letting moisture vapor escape. That’s useful if you’re walking through rain, although waterproof doesn’t mean your feet can never get sweaty. And don’t assume the open mule and slipper configurations will protect your feet the way the full boot does.

Is a $300 convertible shoe worth it?

That’s where we’d have some questions. We haven’t worn the Niobium C1, so we can’t tell you whether the fit stays comfortable in all three setups, how quickly the pieces swap out or how well those zippers hold up over time. And even as a mule, it’s a lot more substantial than a basic slip-on.

Still, we can see the appeal for travel, a rainy commute or a weekend away. Arrive in the full boot, switch to the mule when the weather clears, then use the slipper indoors. If all you need is footwear for serious hiking, a conventional waterproof boot probably makes more sense. We’ve rounded up some of those in our guide to men’s hiking boots.

For $299.99, the Niobium C1 certainly isn’t an impulse buy. But we’ll give New Balance this: it’s doing something genuinely different instead of just changing the color of another sneaker. Whether the three-in-one design is worth paying for comes down to how often you’d actually use all three versions.

Specs and availability: The Niobium C1 is listed at $299.99 in the U.S., with a waterproof eVent-equipped boot setup, EVA cushioning, rubber outsole and three configurations. Check New Balance’s product page for available sizes and colors.