Ferrari has tweaked the design of its halo mirrors, following the FIA's declaration that the support winglets that appeared over them in Spain were illegal.
The Maranello-based team was the first to switch the mounting of its mirrors off the nose and on to the halo.
But its concept raised some concerns in Barcelona when a winglet that the team declared was aimed to support the mirror also delivered a clear aerodynamic benefit.
Following inspections from F1 race director Charlie Whiting, a clarification was issued declaring that while the FIA had no problem with the mirrors, it would only allow extra support elements if there was a minimal aero benefit.
Reflecting on the Spanish GP design, Whiting said at the time: "The interpretation hinges on whether we think that's a mounting or not. We somehow think not.
"They think it contributes to the rigidity of the mirror. I doubt they would be there if there wasn't a measurable aero advantage, but these days that doesn't have to be big.
"We sent a technical directive a few weeks ago in response to a number of questions from other teams about the principle of mounting a mirror on the halo was acceptable.
"We answered yes, and gave a few stipulations, one that it has to be a mounting. It's just a matter of interpretation and such a tenuous interpretation is not something we're happy with."
For Monaco, Ferrari's mirror has been retained in the same position but the support winglet above it has been removed.