Chassis 6061-T6 aluminium (4.0mm) (blue) (standard replacement for all Maxx series)The 4mm aluminum chassis formed from durable 6061 T6 aluminum and then anodized in beautiful blue. Besides forming a rigid backbone for the rest of the truck, the aluminum acts like a heat sink to draw additional heat away from the engine. All of the systems and components are neatly arranged on the chassis for easy cleaning and servicing.