As some Fitbit wearers find amusing ways to skip steps—attaching the devices to hamster balls, ceiling fans, and power tools—a new wrist gadget aims to make sure others never miss one.

The Sunu band smartwatch, designed for people with visual impairments, uses a sonar sensor to detect objects and people within a 15-foot range. When it does, it gently vibrates to alert the wearer, changing intensity as an object or person gets closer. Wearers can also customize the device using an iPhone app via Bluetooth, adjusting for walking speed and to make buzzes stronger or weaker.

Sunu, a company based in Boston and Guadalajara, Mexico, will start shipping the devices for $249 to $299 later this month (plus $50 shipping to the UK).

“I feel much more confident moving around these spaces where normally, instead of walking faster, I’d be like, ‘Uh, where am I going?’” Fernando Albertorio told MIT Technology Review. Albertorio, who is legally blind, co-founded Sunu with two colleagues.

Sunu isn’t the first to come up with such an idea. Some people with visual impairments already use echolocation and tongue-clicks or other noises for spacial awareness and navigation, such as the famous case of Daniel Kish. And other companies have come up with similar wearable devices to detect nearby objects and alert the wearer. There’s also a different type of smartwatch for those with visual impairments, unrelated to mobility, that delivers notifications, messages, and other text in Braille.

But, as MIT Technology Review notes, this new smartwatch is unique in that it could be useful to people along a whole spectrum of visual impairments, from those completely blind to those who just need extra help in some scenarios due to low vision. The National Federation of the Blind reports that as many as 10 million people fall into this spectrum in the US alone.

In a demonstration for MIT Technology Review, Albertorio smoothly navigated the bustling streets of Mountain View California at lunchtime. The device bounces high-frequency ultrasound waves on nearby obstacles, which allowed him to steer around branches and planters and detect doorways by sensing gaps between buzzes. He stopped at an intersection and pushed the crosswalk button by detecting the pole. He said he had even used the device to hike and run a 5K race.

In company testimonials, Howard Sumner said he thinks it “has the potential to be the Fitbit for the blind,” measuring steps, telling time, and helping users find frequently used objects and navigate. Sumner, who recently lost his vision and can now only see light and shadows, said it may not replace his walking cane, but it could be a good companion to the cane. “There’s tremendous potential for this technology to assist visually impaired and blind people.”