Thank you very much for your encouraging comment! I appreciate it.

I did not understand the power of the battery of the 15 inches zbook in wh Thanks

Hi Stefan, thank you for your question. Optional backlit keyboard means that if you want to have a backlit keyboard, that is to say one that lights up in the dark so that you can see the keys when the lights are off, you can order the computer with it. However, if you prefer not to have one, say if you usually use your computer in the daytime, or in well-lit rooms and turn the lights on in the evening, then you can order the computer without it. It is up to your preference. I like a back lit keyboard so I can see the keys in the dark even though I mostly use the computer with the lights on. However, if my next computer did not come with it, I am sure I would be okay without it. In either case, backlit keyboards do use up the battery more, although they do not effect the performance benchmarks of the computer. I hope that helps.

ZBook: higher performance machine.

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