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It's a system Steem added that basically works like leasing Steem Power - you get ~8.7x as much SP for a duration of 90 days (which can be extended at a slightly discounted rate) as opposed to buying it directly at a 1:1 ratio. A lot of people use it to get more power for their upvotes or to increase their bandwidth when first starting out.

what is the proses of this system

I also wanna know.

For yourself, you can simply choose "Steem Power Delegation" as your output coin and create it like a normal trade. We will also send a link in an encrypted message to your Steem account that takes you to a personal page where you can purchase more time for your delegations. Once the time runs up our system automatically takes the delegation back, so there's nothing further you need to worry about.