Three years in the making, and Dreem has come true. The sleep-tracking wearable, made by Paris and San Francisco-based startup Rythm is now available for pre-order. Along with the public debut of Dreem, Rythm also announced the company’s funding to date stands at $22 million, an $11 million increase since they last raised money in March 2016.

The $499 Dreem headband uses dry polymer electrodes to track a user’s brain activity during sleep, generating data for analysis on an internal CPU. The device– which the company describes as “designed to feel like loungewear” – also actively works to help users fall asleep and have more restful slumber by emitting a series of subtle, precise sounds directly to the inner ear via a process called bone-conduction technology. A companion app allows users the ability to visualize sleep patterns and history. The product is scheduled to start shipping to customers this fall.

Dreem has been through hundreds of iterations, the company said, and early tests of the product in limited release showed a decrease in the time it took users to fall asleep as well as a lengthened time spent in deep sleep.  

"Rythm started with one single idea — to monitor and influence brain activity based on auditory stimulation to enhance sleep quality," Rythm CEO and cofounder Hugo Mercier said in a statement. "Now after our successful beta program, we have validated the science and learned from more than 500 users on what the headband can do. The launch of Dreem is a breakthrough moment and we are thrilled to get our product to consumers so they can get on the path to better sleep."

Mercier first began toying with the idea of a sleep wearable when studying for his masters at Ecole Polytechnique. The company was founded in 2014, and went on to have a well-known design firm (fuseproject) onboard with the development on Dreem. The company’s scientific advisory board also boasts some big names in digital health, including Stanford University’s neuroscience professor David Eagleman (who is also founder and CSO of neurocognitive assessment software company BrainCheck), and Dr. Emmanual Mignot, who is the director of Stanford’s Sleep Center.

"Rythm has developed technology that has the potential to change how people perceive their sleep, while also giving users new tools to improve their well-being," Mignot said in a statement. "The vision of the company and the team behind Dreem is exceptional. To have a solution like Dreem that makes sophisticated medicine accessible to anyone represents a powerful step forward."

Hacking into the growing sleep tech market is apparently a dream of many. It was the topic du jour at the Consumer Electronics Show in January, Apple just recently acquired sleep startup Beddit a month after the company’s sleep expert left.

However, the sleep space has been notoriously difficult area to stay successful in. Just this week, Silicon Valley sleep-monitoring company Hello shut down, even though it had been a much-hyped and well-funded startup since its landmark crowdfunding campaign in 2014.