Pre-order information of the OnePlus 9 series have leaked.The flagship phones could be accompanied by pre-order presents for early buyers.OnePlus revealed the other day that it has something to announce on March 8. Word has it that well get a main launch date for the OnePlus 9 series on that day. Now, tipster Evan Blass has gone ahead and leaked some pre-order details for the supposed OnePlus 9 and OnePlus 9 Pro.According to Blass, the 2 phones will go on pre-order on March 23. That means we may just see them launch on the same date or some time better to it.Blass likewise revealed that the OnePlus 9 and 9 Pro would be accompanied by pre-order gifts for early purchasers. He declares that those who buy the OnePlus 9 will get a complimentary set of the regular OnePlus Buds Z. Meanwhile, OnePlus 9 Pro buyers will get the Steve Harrington Edition of the real wireless earbuds.Blass goes on to state that if the business is planning to release the rumored OnePlus 9R or the OnePlus Watch together with the OnePlus 9 and 9 Pro, the devices wont be accompanied by any pre-order freebies.Unfortunately, the tipster didnt expose more than this. We still do not have a rate leak for the phones, although we expect them to cost around the like in 2015s OnePlus 8 flagships.Head to our dedicated OnePlus 9 series rumor center to understand more about the upcoming phones.