crwdns2933423:0crwdne2933423:0

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crwdns2933797:0Jeff Suovanencrwdnd2933797:0crwdne2933797:0

crwdns2936043:0crwdne2936043:0 crwdns2933505:0crwdne2933505:0 Jeff Suovanen

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[* black] Last call: back cover. It's press-fit over a teflon-like O-ring, but a thumbs-up and a firm push relieves it of duty.
[* black] The material has been standardized across watch models and souped up to snazzy ceramic, replacing the previous Ion-X or Sapphire options.
[* black] It also houses the [https://en.wikipedia.org/wiki/Photoplethysmogram|PPG sensor array|new_window=true] that is responsible for sensing heart rate.
[* black] It would've been cool to see some change from [guide|67385|the Series 2|stepid=136503|new_window=true] after [http://appleinsider.com/articles/15/10/23/apple-watch-users-complain-of-inaccurate-heart-rate-readings|complaints about accuracy|new_window=true] in previous models. As far as wearables go, however, the Apple Watch [http://appleinsider.com/articles/17/05/24/stanford-study-finds-apple-watch-top-notch-heart-rate-monitor-mediocre-calorie-counter|is the best of the bad|new_window=true].
[* black] Also it appears that the wireless charging coil has been slightly modified to support ''[https://www.theverge.com/circuitbreaker/2017/9/22/16349480/apple-watch-series-3-qi-wireless-charging|most|new_window=true]'' Qi wireless chargers.
-[* black] Lastly, here's a better peep at that [guide|97521|barometric port|stepid=179039|new_window=true] we mentioned earlier.
+[* black] Lastly, with the new barometric altimeter taking the spot next to the microphone, where did the air vent go? Answer: hiding out right here, next to the diagnostic port.