True to its word, BMW is now openly driving its new hydrogen fuel cell prototype in public.

BMW gave the first glimpse of its new fuel cell vehicle (FCV) earlier this month and said testing would begin before the end of July. Now, the German carmaker is granting the first “listen” as it stretches the legs its fuel cell car for the first time on public roads.

The hydrogen prototype – which is still unnamed – resembles the i8 used as its base. The prototype’s steeply sloping windshield, pointed nose and even the upward opening scissor doors have all been borrowed from BMW’s $136,000 hybrid supercar.

The most notable design changes are in the front, including a set of pinched headlights that peer out over three enlarged grille sections. Matte black paint adds to the FCV’s glowering appearance.

And the sound of BMW’s hydrogen car is as unusual as its appearance, or perhaps a bit more. From the outside, the FCV is about as quiet as a battery electric car. The friction from the tires on the pavement seems to makes up much of the car’s on-road noise.

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As the car passes by, it makes a distinctive whirring in a pitch that almost matches the ambient crickets. That’s the sound of hydrogen feeding the FCV’s 180-kilowatt electric engine, and the resulting water vapor leaving the tailpipe.

If the current timeline holds firm, BMW won’t have a production ready FCV for about five more years.

BMW will release “a technically mature, customer-ready vehicle some time after 2020,” according to Matthias Klietz, the head of engine research.

That gives the carmaker plenty of time to further experiment with the FCV’s look, and sound.