Sandbar Pushing 'Stream' to Turn Finger-Tapped Whispers Into AI Thought Notes

Former Meta engineers Mina Fahmi and Kirak Hong spent two years operating in stealth to build a wearable device that fits on an index finger.

Their startup, Sandbar, raised $36 million in funding from venture firms Adjacent and Kindred Ventures to manufacture and distribute the product.

Credit: Sandbar

The device, called the Stream Ring, skips health tracking features like heart rate monitors or sleep sensors. Sandbar designed the physical ring exclusively as a voice-capture device and thought organizer.

Users wear the aluminum band on their index finger and raise their hand to whisper into the microphone. The microphone stays powered off until the user presses the glass touchpad on top, which sends a small haptic buzz to confirm recording.

"Importantly, I wanted that experience to feel like inner dialogue, not a conversation with a virtual companion," Mina Fahmi, CEO and co-founder of Sandbar, stated in an official release detailing the hardware design.

Sandbar constructed the ring with an aluminum exterior in silver or gold finishes and a black resin inner lining. The entire chassis carries splash-proof water resistance, allowing wearers to keep the ring on during rain or routine handwashing.

The directional microphone requires close proximity to the mouth, capturing spoken whispers without broadcasting audio to surrounding people. The internal memory saves audio locally if the user moves out of cellular range or loses phone battery power.

Once reconnected to an iPhone, the ring syncs stored recordings with the companion iOS application. The app converts raw audio into text notes, organizes topics, and creates actionable task lists.

The glass touchpad double-functions as a media controller for playback. Wearers tap and swipe the panel to play music, pause tracks, skip songs, or adjust playback volume.

An internal battery powers the device for a full day of active use before requiring a recharge via USB-C. Sandbar includes a custom sizing kit with every order so buyers can select ring sizes between 5 and 13.

Credit: Sandbar

Multiple AI models power the background processing inside the iOS application. The software handles live transcription, groups related ideas into folders, and rewrites notes upon request.

A feature called Inner Voice lets the software speak back to the user. The application generates an artificial audio model that mimics the user's vocal cadence and tone.

"We're trying to give people themselves plus a little bit of whatever additional thing they need, an additional perspective, additional memory, empathy, or creativity."

Fahmi explained the goal of the voice synthesis system during a product demonstration at Sandbar’s Manhattan office.

Testing data shows active engagement among early adopters. Testers record voice notes over 50 times per day to organize work presentations, prep travel itineraries, and track daily schedules.

Pricing, Production, and Software Roadmap

Sandbar priced the silver aluminum Stream Ring at $249 and the gold finish at $299. The initial preorder batch sold out completely, prompting Sandbar to open a second production wave.

Orders ship with three months of access to Stream Pro, a subscription tier offering unlimited AI interactions. The subscription costs $10 monthly after the trial period ends.

Sandbar plans to start delivering the first hardware shipments during summer 2026.

Engineering teams are now building a desktop web platform to manage saved audio archives. The developers are also working to reduce processing latency and build autonomous AI workflow tools that complete actions based on recorded voice commands.