In addition to the existing Watch sizes, there's a new, larger and heavier Pro model with a more durable titanium build. Samsung says both Watches have longer battery life over earlier models thanks to higher-capacity batteries (590 mAh in the Pro), an infrared skin temperature sensor and a more durable sapphire crystal for the watch face instead of Gorilla Glass. Plus, there will be new faces available.
There's a larger surface area for sensor contact on your wrist, which Samsung says will provide more accurate results, and a smaller combined sensor size.
Samsung's offering some trade-in discounts on preorders: $75 off the Watch 5, or $125 off the Pro if an "eligible" watch is traded in, along with a $50 credit for accessories.
Read more: Samsung's Galaxy Watch 5 Now Includes a Pro Model and Better Battery Life