The visuals are just part of what's new, however. The Digital Crown (which has a red ring instead of the glaring red dot, we'd note) now incorporates haptic feedback. You can count on a speaker that's 50 percent louder and a microphone position optimized for call clarity. Even the materials have received an upgrade, as you'll now see greater uses of ceramic and sapphire.

Some of the largest upgrades are under the hood. The 64-bit, dual-core S4 chip promises to be up to twice as fast (over what Apple didn't say, but we're presuming the Series 3). A next-gen accelerometer system is not only much more precise but also smart enough to detect hard falls -- it'll offer an emergency call if it thinks you've tumbled. And crucially, this is the first over-the-counter, FDA-approved device with a built-in electrocardiogram sensor. Put your finger on the crown to create a closed circuit (the sensor is on the bottom of the case) and the watch will give you an ECG that could identify heart conditions.

Series 4 will still have the same claimed 18-hour battery life, Apple said, but you now have six-hour longevity for outdoor workouts. You won't be scrambling for a charger quite so quickly after a run then.