This replacement is designed to be the most strong one to strenghten the framestructure of the Walkera Runner 250 V1 2015 to make it very rigid against crashes.With a lower base plate and brackets to reinforce the Frame it is giving the Frame the final strengh.This also results in a much better flight performance.By the way a major issue of the Runner 250 is solved, the battery is fixed once and for all.The nacessary washers to be placed inbetween the upper CF Plate and the PDB are included now.You´ll need 4 pc. 2,5 x 10-12 mm PT screws to fix it to the upper Frame members.As an option: The screws can be ordered for $ 3.99 incl.transport at mail@coterconnection.de find the Manual here: https://www.dropbox.com/s/k7nuugnzoqjnfx6/Manual%20battery%20tray%20%281%29.pdf?dl=0