Servo to be used instead of the conventional 3mm washer when mounting the servo To support the upper and lower two holes in one plate, the mounting strength of the servo And up, it can suppress the servo deviation such as the time of the crash. To protect the servo case that there is time to further collapse in tightening too much at the time 3mm washer use.It will protect the nest. Blue anodized finish that matches the aluminum servo stay and the color is made of aluminum.