Lasting even longer than the Apple Watch Ultra 3... a smartwatch that lasts 400 days on a single charge appears

Open-source smartwatch project LightInk has been unveiled.

It uses an e-ink display and solar-assisted charging, with claims of up to 400 days of battery life.

The device takes a different approach from mainstream smartwatches by prioritizing simplicity and power efficiency.

Its release highlights an alternative design direction in a market focused on higher performance.