Vesper, a Boston-based manufacturer of advanced microphone tech, announced a new round of funding today worth $23 million. The incoming cash is led by American Family Ventures, and includes Series B investments from Baidu, Bose Ventures, Sands Capital and Amazon’s Alexa Fund, among others.

It isn’t Amazon’s first fling with Vesper. In 2016, the Alexa Fund joined Vesper’s $15 million Series A funding round, and has since incorporated Vesper microphone tech into special, Amazon-tested hardware kits that manufacturers can use to make their own Alexa devices.

Calling Amazon’s investment “a testament to [Vesper’s] continued momentum,” Alexa Fund director Paul Bernard suggests that Vesper could play an important role in Alexa’s march into the mainstream at a time when voice-activated gadgets continue to surge in popularity.

“Our vision is for Alexa to be everywhere, and that means devices need to be built with durable, high-quality components that stand up to the demands of many different environments, especially on-the-go scenarios that require better power efficiency,” Bernard says.

To that end, Vesper’s flagship product is the VM1010, a micro-sized, waterproof piezoelectric microphone with “Zero Power Listening.” Vesper claims that its proprietary approach can bring voice activation to battery-powered devices while using “nearly zero power,” and that its manufacturing partners stand ready to scale to “any volume.”

The incoming cash brings Vesper’s total funding up to $40 million.

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