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Since its debut way back in 2015, each iteration of the Apple Watch has come with newer and, well, better features. The Series 3 was the first with cellular, Series 4 increased the display and Series 5 gave us an always-on display.

For the Apple Watch Series 6, though, Apple didn’t stop at just one bill-topping enhancement, but tried to push things even further with a host of new features. There’s the faster Apple-made S6 chip inside, an always-on altimeter that always calculates your elevation and the ability to monitor blood oxygen levels. And some new colors.

We tested the Apple Watch Series 6 for nine days. After more than a few sweaty workouts, many blood oxygen readings, full battery cycles and using it in a variety of situations we think that, while this isn’t the biggest update ever to the Apple Watch (and anyone with a Series 5 would struggle to see noticeable performance changes), the Series 6 keeps the Apple Watch ticking forward.

New colors, but sticking with a familiar design

In terms of design, Apple is ticking that ol’ “if it ain’t broke, don’t fix it” box.

Though it’s the design we’ve pretty much come to expect, it still feels pretty fresh for 2020. There are a few new paint jobs for Series 6 as well. In the aluminum finishes, the Series 6 now comes in blue and (PRODUCT)RED in addition to silver, space gray or gold. The stainless steel options come in an updated polished gold or graphite finish. The latter, paired with the matching Milanese loop (a stunning magnetic stainless steel watch band), makes for an epic watch.

Like many, we were pretty jazzed about the new Solo Loop bands, but in testing we noticed a big thing: sizing can be wonky. Apple recommends you measure by printing out a sizing guide (you can also get one in store), but we measured in at size five. Truth be told, that band was a little loose, and while we might just have a small wrist, our best guess is that you might want to size one down to ensure a snug fit. Whether it was silicone or woven Solo Loop, we ended up feeling better with a size 4. We’ll continue to test the band sizes and will report back.

No matter the color or type of band attached, your Apple Watch still has a Digital Crown, a microphone, and an action button on the right hand side. That Digital Crown still has the red circle and features haptic feedback. The left houses speakers. In our case, the 44mm screen is stretched to the edges and the bezels are pretty much the same size as a standard watch. The entirety of the Series 6 is rated WR50 and is swim proof. More precisely, it’s water-resistant up to 50-meters and if you do wear it swimming or in the shower (we won’t judge), just remember to eject the water with the handy software tool. Essentially it plays tones to push the water out from the speakers.

At just 10.7-millimeters thick and only 36.4 grams (for the aluminum 44mm Series 6), there’s something to be said at the engineering marvel that’s taking place here. Apple packs a lot into the Apple Watch and it doesn’t weigh you down like some other watches. We’ve worn a pretty sizable non-smart Nixon in the past and it weighs more.

Over on the rear side, you’ll see an updated sensor array, the electrical hardware that powers heart rate, ECG (electrocardiogram) and blood oxygen monitoring on Series 6. And when holding the Series 6 and Series 5 next to each other with the face down, you can see the sensor is a new piece of hardware. There’s an electrical heart rate sensor for ECG and an optical heart rate sensor in its second generation. This is also where the Series 6 gets a leg up over the Apple Watch SE. But, most importantly, there are eight sapphire crystal windows with LED clusters and photodiodes that are used for measurements, namely blood oxygen.

The sensor tech in this core wrist-facing portion alone is big. The Series 6 still features an accelerometer, gyroscope, compass, always-on altimeter and GPS. On the rear side are two tabs that you press in to swap the different bands in or out. The excellent news is that all previous Apple Watch bands work on Series 6. And if you are upgrading from a Series 0, 1, 2 or 3, the 38mm bands work with 40mm and 42mm work with 44mm. A continued surprise from Apple, allowing consumers to reuse some pieces from older Watch models, but definitely a welcome perk.

Blood Oxygen joins the well-being party

As we wrote in our first impressions of the Series 6 and teased above, blood oxygen monitoring is the big feature of this Apple Watch. As Apple has done since the inception of the Watch, well-being and activity tracking have been a core feature. They’ve just added to it and will continue to do so. From heart rate to electrocardiograms on your wrist and now the ability to take a blood oxygen reading.

And a blood oxygen reading is essentially presenting you with the oxygen saturation. It’s an important metric that can indicate how much oxygen is flowing through our body. And on the Series 6, Apple added the ability to perform what a pulse oximeter does.

With the array of four infrared LEDs and the four photodiodes on the back of the Apple Watch, it broadcasts light through your wrist (passing the skin) and onto blood vessels that run through the arm. The photodiodes capture the reflection or the color of the light reflected back to the sensor. Algorithms and the sensor itself measure the amount of oxygen in your blood and deliver the result. The brighter the color, the more saturated. It takes just 15 seconds to take a measurement on-demand, the Apple Watch can also take them throughout the day and even overnight. As with all other data, it’s all housed on your connected iPhone in the Health app.

Now that we know how the Apple Watch can take these measurements, let’s talk about how it performs. We’ve been wearing the Apple Watch Series 6 for over a week and along the way have also been testing a ChoiceMMed Pulse Oximeter on our finger. As we wrote in our first impressions piece, the Apple Watch Series 6 was consistently within a digit (either above or below) of what the Pulse Oximeter was finding.

We’re not using those readings to make any medical diagnosis (which both Apple strongly warns not to do). Same as with the Heart Rate sensor or when taking an ECG, the Apple Watch gives you insights into your body and health, but it doesn’t aim to diagnose.

When taking a blood oxygen reading on the Apple Watch Series 6, you’ll want to keep your hand and arm still. We tried taking one while riding a Peloton and the Watch delivered an “unsuccessful measurement” screen. And when those arise, the Series 6 tries to troubleshoot by sharing recommended ways to get a proper result.

In our week of testing, we only had three or four notable unsuccessful measurements, and most of the time it was due to our arm not being flat or it moving. For the most part, it’s been easy enough to use and the 15-second measurement time is spot on. We’ve found that after about day three, it got closer to delivering the same core measurements as the PulseOX sensor.

You can still take heart rate readings with just the tap of an app, the Series 6 can also take these in the background and even alert you if your heart rises for a period with no activity detected. The big Apple Watch feature that premiered on the Series 4 is here as well: the ability to take an ECG. It still takes 30 seconds to measure and requires a finger to be resting on the Digital Crown.

The Apple Watch Series 6 can also track sleep in a very Apple fashion. Essentially, Sleep Tracking aims to help you meet your goals and to track how long you were asleep. For us, it makes attaining seven hours of sleep a night a bit easier. It focuses on the positives and working to attain your goals. It uses sensors to monitor movement overnight, along with heart rate and blood oxygen readings, so the bigger battery here helps a lot.

Also packed into watchOS 7 was handwashing tracking. Essentially, the watch can detect via motion and sounds that you are washing your hands and present a 20-second countdown. Via location tracking, it will remind you to wash your hands once you return home as well.

Small differences in performance

With the Series 6, there are clear improvements over the Series 3 and Series 4, with slimmer ones in terms of pure speed over the Series 5 or even the SE.

The biggest improvement over all previous models, including the Series 5, would be the speed of Apps launching — especially the third party ones. The App Store on your wrist opens a lot sooner and it feels a little bit more seamless as a whole. You can easily browse and opt to download an app when at times in the past we were met with some slowdowns. Siri is a lot more responsive and usable here as well. You can see your request processing quicker and appearing on-screen, plus she’s a lot swifter in delivering the correct response. You can even use Siri for translations right on your wrist.

With over a week of testing, we still find ourselves charging the device at least once a day. We’re used to getting about a day and a half of use from the Series 5, but sleep tracking makes this a little more complicated. We’re still able to get a full day of use out of Series 6 and it does meet the 18 hours expectation that Apple promises. The other good news is the Apple Watch charges faster. You can go from 0% to 80% in an hour and 0% to 100% in just an hour and a half.

And would it be a new Apple Watch without some new watch faces? We’re digging the Count Up display for it’s classic watch vibes and the ability to customize it with four complications in each corner. There’s also a Memoji watch face, in which we have well ourselves on our wrist. There’s also a quite nice Typography face which lets you have some fun different fonts.

Bottom Line

Simply put, the Apple Watch Series 6 is the best Apple Watch yet. It doesn’t deliver a radical redesign, but we’re getting closer and closer to perfection. Health and wellbeing get even better with blood oxygen monitoring. The overall performance is quicker and more efficient thanks to the S6 processor inside.

We see the Series 6 as a no brainer upgrade for those with anything before a Series 5 – that means if you have a Series 0, 1, 2, 3 or 4 we’d recommend the upgrade. You’ll get a better experience all around and have many more features. Have a Series 5? Well, you’ll need to decide if the new health features are that important to you. It won’t be the biggest performance boost, though, and battery life is pretty much the same.