Forward-looking: Many tech companies are embracing environmentally friendly initiatives, but one Finnish firm is taking this to the next level with the world’s first microbe-grown set of headphones.

Eschewing the usual materials you’d find in headphones in favor of biodegradables such as yeast, fungus, and bacteria, the Korvaa is a joint effort from Finnish design company Aivan, VTT Technical Research Centre of Finland, and Aalto University.

Fast Company reports that the rigid plastic in the Korvaa headphones, including that found in the headband, is 3D-printed using a bioplastic created with the lactic acid produced by yeast. The ear padding is made from a foaming protein called Hydrophobin that’s produced by fungus and mixed with plant cellulose. The fake leather also comes from fungus, while the inner mesh that sits over the speakers is biosynthetic spider silk produced by microbes. The outer foam is a mycelium-cellulose composite.

The Korvaa headphones, which were presented at the SingularityU Nordic summit in Helsinki, are a prototype design, which means they lack any electronic components that allow them to work as an actual listening device.

“Basically, weight-wise, it feels like your typical pair of headphones, except all electrical components and mechanics [hinges, etc.] are missing from this product concept,” says Aivan cofounder Thomas Tallqvist. “We hope to develop it further in the future.”

While we’re not going to see working Korvaa headphones available to buy anytime soon, the prototype illustrates the wide range of devices that can be created from biomaterials. With millions of tons of e-waste being generated every year, that can only be a good thing.