Apple has introduced the iPhone 6S and iPhone 6S Plus, the latest versions of its flagship smartphone. Both phones will be released on September 25th, and Apple will open preorders on September 12th. On a two-year contract, the iPhone 6S starts at $199 for the 16GB model, and moves up to $299 for 64GB and $399 for 128GB. The iPhone 6S Plus 16GB model starts at $299, and costs $399 for 64GB and $499 for 128GB. Since most carriers are moving away from two-year contracts toward payment plans, Apple also listed typical installment plan prices; the 6S will be available from $27 a month and the 6S Plus from $31. Finally, Apple is also offering a new payment plan for $32 a month, which lets you lease an iPhone with an AppleCare+ warranty and return it for a new model every year.

Read next: The iPhone 6S review.

As with other "S" releases, most of the changes to the latest iPhones are about new features. There's a new rose gold finish, and a custom type of aluminum for the phone's case, but the big story is what's on the inside. The new iPhone 6S and 6S Plus have been given the usual spec boost with a new A9 processor that Apple says is 70 percent faster than its predecessor. One of the biggest new features is "3D Touch," a new pressure-sensitive touch feature that allows iPhone users to press down on the phone's screen to perform context-sensitive actions.

Hands-on with the new iPhone 6S and iPhone 6S Plus

Apple Event: iPhone 3D Touch demo