Topic summary
Apple Watch Series 3

Extracted from the Wikipedia article Apple Watch.
Third generation (Series 3)
The Apple Watch Series 3 features a faster processor, the dual-core S3, Bluetooth 4.2 (compared to 4.0 on older models), a built-in altimeter for measuring flights of stairs climbed, increased RAM size, and is available in a variant with LTE cellular connectivity. Siri can speak through the onboard speaker on Apple Watch Series 3 due to the increased processing speed of the Watch.