Ahead of Apple's September event, some things about the high-end iPhone X remained a mystery despite a lot of pre-event rumors regarding the $1,000-plus smartphone. On the other hand, the Apple Watch Series 3 proved entirely predictable—we knew its distinctive feature would be standalone LTE service.

WatchOS 4 WatchOS 4 is the latest software update to hit all Apple Watch models. The Series 3's launch coincided with its rollout. However, only a few things are unique to the Series 3 Watch models on watchOS 4: LTE service, Siri speaking, and barometric altimeter calculations. We'll be discussing all aspects of the Apple Watch Series 3 in this review, but read our WatchOS 4 is the latest software update to hit all Apple Watch models. The Series 3's launch coincided with its rollout. However, only a few things are unique to the Series 3 Watch models on watchOS 4: LTE service, Siri speaking, and barometric altimeter calculations. We'll be discussing all aspects of the Apple Watch Series 3 in this review, but read our watchOS 4 review for full details on the latest software update.

Wearables with LTE connectivity aren't new, but the feature is new to the Apple Watch. So the move still marks a huge update to an Apple device that's been around for less than three years. And it's a big gamble for Apple considering other wearable manufacturers have tried (and largely failed) to make a good cellular wearable experience.

The Apple Watch Series 3 ultimately comes in two types of models: with LTE and without LTE. Those who opt for the $399 LTE models expect the ability to make and take phone calls, respond to text messages, and check alerts even when their iPhones are miles away. I've spent just about a week with a Series 3 with LTE, and I have gotten glimpses of what it feels like to be successfully free of my iPhone. However, there were some problems for those of us who first tested the device, so I'm also quite familiar with what it feels like to be completely alone when wearable LTE fails.

Design

The Apple Watch Series 3 looks and feels nearly identical to the Series 2. Aside from being ever-so-slightly thicker, the Series 3 doesn't deviate much from the previous model. The only noticeable visual difference is the red dot on the Digital Crown that those who purchased an LTE model will have to endure. Each untethered Series 3 model now has the equivalent of a little red nose on its right edge, and it's only there to indicate a LTE-connected device. I don't represent all types of Apple Watch users, but I don't think many people will forget they paid $399 for a tiny iPhone on their wrists.

Also, red isn't my color, so the dot ends up clashing with most of my preferred wristbands. Thankfully, the dot is small enough that most passersby won't see it. I mostly wore my 42mm Series 3 with one of the new Nike Sport Loop wristbands, which is comfortable for all-day wear. It's designed to be breathable for exercise and more adjustable than other bands thanks to its Velcro-like closure. I have small wrists, and regular bands for the 42mm tend to be too large for me. I like that I can adjust the Nike Sport Loop to the right tightness and still get accurate heart-rate readings.

As iFixit found in its Series 3 teardown, many of the Series 3 internals are the same as the Series 2. However, there are some important differences in the LTE models, particularly the addition of a slew of RF chips that presumably enable the standalone cellular service. Unlike other cellular-connected devices, the Series 3 has an eSIM inside rather than a regular SIM card that you could remove on a whim. The Series 3 with LTE models have the same second-generation OLED Retina display with Force Touch that the Series 2 has. This time it doubles as a multifrequency antenna.

Apple touted the new addition of a barometric altimeter in the Series 3 Watch, which lets it count how many flights of stairs you've climbed each day. However, iFixit found a barometer in the Series 2 as well—this hardware may not be totally new, but it's possible that Apple activated it in the Series 3 and accompanied it with software in watchOS 4 so it can quantify stairs climbed. That metric now shows up on the Watch in the Activity app and in the corresponding iOS app. The wireless charging coil also appears to have been modified slightly, possibly to support Qi wireless charging. Apple explained that its forthcoming AirPower charging pad will let users charge multiple devices at once, including the Series 3 Watch.

The new processor is a big deal in the Series 3 Watch because Apple claims it improves performance by 70 percent. The new S3 chip certainly made my Series 3 with LTE feel slightly faster than my Series 2 Watch (both running watchOS 4). App transitions, watch face animations, scrolling speeds, and more benefit from the improved processor. As mentioned in our watchOS 4 review, my Series 2 Watch slowed down a bit after updating to the newest software. While that wasn't slow enough to cause major problems, the Series 3 is certainly primed for running watchOS 4 in contrast.

With the introduction of the Series 3, the Apple Watch Series 2 will be phased out. It's a shame, because the Series 2 represented a great update from the Series 1 Watch. However, this move is understandable considering the Series 3 is available in non-LTE and LTE versions. Anyone tempted by a Series 2 in the past could opt for a non-LTE Series 3, which has the dual-core processor, stairs-climbed tracking feature, and a mic-ed up Siri, in addition to the standard features found in a Series 2. The Series 3 models without LTE start at $329 while the Series 3 Watches with LTE start at $399 (and that doesn't include the carrier-specific monthly charges).