The main center plate for the Mongoose QuadCopter Frame. You need to also print the carrying plate and the arms for this to be functional.
Print the top and bottom plates. Then print the arms. After printing the arms, place them in the mounts and sandwich them together with the top and bottom plates. Use M3 bolts and two washers and an M3 nut on all mounting points. Bolt the electronics carrying plate and the arms to this plate. Mount your battery box and escs to the frame as well.