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They are massive mining factory, with lots of hash power.
So they sell mining contracts for particular periods. That is a great way to earn some cryptos without spending too much time online.
more informatio here:

thanks @ansisltd for attending @rakitera query.

Additional info and tip: if you wish to have quick return, you need to invest more; to take advantage of bitcoin's advancing price.

In every investment, there's always a risk that you need to conquer. I did it, you can do it too.

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