This $4,000 iPhone X has its own solar battery - and the first one will be mailed to Elon Musk

A Russian accessories maker called Caviar just released one of the most expensive iPhones you can buy.

The iPhone X Tesla is a customized iPhone X plated in carbon and gold with a built-in solar battery. The device starts at more than $4,000, and comes in its own wooden carrying case.

Caviar is known for making elaborate accessories that cost thousands of dollars. What makes the cases different is that they're not removable - Caviar adheres its designs directly to the device itself.

But the Tesla device - named because of Elon Musk's commitment to sustainable energy - is Caviar's first with its own solar battery.

Here's how it works.

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