McLaren have a fallback option if Formula One race stewards take issue with their new car's rear wing but are confident they won't need it before Sunday night's season-opening Bahrain Grand Prix.
Managing director Jonathan Neale says McLaren aren't using a a radically different design and are confident the car their world champions Jenson Button and Lewis Hamilton will drive is legal.
But Neale says you never know what the stewards are going to do on the day.
Red Bull's team principal Christian Horner has questioned McLaren's rear wing , while saying Ferrari appeared to be more concerned about it than his team.
However a Ferrari spokesman says they know of no concerns while McLaren say they've consulted the FIA throughout the design process.