The curved side rails are made from corrosion resistant aluminum tubes, which offer full width impact protection along the entire length of the unit. The side rails were designed to re-direct errant vehicles away from the rear of the truck (coffin corner). Other manufacturers Crash Attenuator models have little or no side-angle impact protection.
The aluminum boxes are filled with a moisture proof, aluminum honeycomb material. The boxes, together with the curved side rails, absorb the energy from an impacting vehicle. The aluminum boxes are painted with a bright yellow powder-coated finish, for lasting durability.