This servo tray allows you to mount stronger and more precise servos in the ParkZone Radian Pro to improve tail performance. The stock servos do not center well, which is particularly problematic on the elevator, which must be trimmed precisely for the plane to glide consistently. The tray accepts a Hitec HS-82MG for the elevator and a smaller HS-65MG for the rudder. To mount it in the plane, remove the original servos, test-fit the tray and cut away foam as needed so the tray fits into the bay. The back of the plate rests on the same surface as the tabs of the original (3W) servos. Once you have the tray fitting properly, hot glue it in with a bead of hot glue around the edge. You may also wish to consider replacing the ESC with one that can provide more current to the servos.