The D413 Floating Servo Mount is an optional product for our Hard-Anodized Aluminum Chassis. Traditional servo mounting in 4wd cars is done by mounting the servo to the chassis with two mounts that offest the servo to a particalr side of the car due to the drive train using all the center real-estate. Your vehicle will twist around its center line axis during cornering which means the most twisting takes place the further away from the center of your car. So what does this have to do with your servo you might ask? With the dual mounts and offset location, your servo is acting as a chassis brace which doesn't allow the chassis to absorb the energy (twist) as easily as the other side. And luckily some very smart people in the on-road community recognized this and innovated the floating servo mount that acts as crane of sorts to swing your servo out from the center of the car while securely holding it just above the chassis so it can freely twist the night away if it wants on both sides.