Between the first and second tests of the 2019 pre-season, the Formula 1 teams made varying degrees of changes to their new cars. Some were happy to focus their developments on making sure the internals were fully optimised, which meant that external changes were minimal.
But others cast their eyes towards tweaking more visible portions of their cars as the engineers continue to get their heads around the demands of the 2019 rule changes.
Mercedes returned for the second week of testing with a heavily-upgraded aero package, attempting to address a number of problem areas with the new W10. But elsewhere on the grid there were plenty of other areas of intrigue, as the teams made the most of the final opportunity to test their new cars before the season begins in Melbourne. Here are the main items that caught Giorgio Piola's eye in the final days of winter running.