The 6S Plus follows the same metal style as the 6 Plus before it. Looking at the outside, it's hard to distinguish it from last year's model. They use the same casing design, though the 6S Plus uses new aerospace-grade aluminium, instead of the older aluminium casing.
The iPhone 6S Plus has the same 5.5-inch Retina display as last year's version. The screen is protected with brand-new glass, however, which Apple claims is the strongest in the industry.
Compared with the iPhone 6 (right), the 6S Plus looks hefty, but you do get that extra display real estate.
Apple has made the biggest camera update since the iPhone 4S by giving the 6S Plus (and 6S) a 12-megapixel main camera. It can record 4K video, and Apple asserts that it shoots sharp, detailed photos.
Around the front is a 5-megapixel camera for FaceTime and selfies.
The iPhone 6S Plus comes in silver, gold, space grey and a brand-new rose gold colour.
The gold looks pretty sharp whether you're inside in a dim hotel bar or out in bright sunlight, like you see here.
One of the main new features on the 6S and 6S Plus is 3D Touch. It makes the touchscreen pressure-sensitive. Push in, and you can actually make things happen: new options pop up on the screen, offering you shortcuts without needing to actually go into an app.
Compare the iPhone 6S Plus and the iPhone 6 Plus and the only way you might be able to tell them apart is the telltale S insignia on the back.
The bottom edge is where you'll find the speaker grille, Lightning charging port, headphone jack and microphone.
The volume rocker and mute switch are on the left-side edge.
You'll recognize the round Home button, the handsets' only physical control.
Touch ID is still an integral feature in the iPhone. The fingerprint sensor is built into the home button.
As always, you can arrange the icons on the display just as you want.
The biggest upgrades to the iPhone 6S Plus are on the inside and in the software. The phone is powered by a third-generation 64-bit A9 chip that promise speedier performance. Also new is 3D Touch, a new way to interact with what's on the screen. Press and hold the display to call up a menu with app shortcuts and more.
The 6S Plus is just slightly thicker (0.29 inch or 7.3mm) than the iPhone 6 Plus (0.28 inch or 7.1mm) from 2014, but both have nearly identical shapes and styles.
For more about the iPhone 6S and iPhone 6S Plus, check out CNET's coverage: