For the high downforce requirements of the circuit in Monte Carlo, McLaren have designed a new rear wing. The new item now features a completely horizontal leading edge, ditching the curvature in the middle. The resulting lower leading edge will allow the wing to catch a little more air and hence create a stronger downward force.
Additionally, the team also looked at Toyota's central third element, only allowed in the middle section of the wing. While not applicable for the complete wing, this small section will see an improved aerodynamic efficiency compared to a two-section wing.