Formula One testing gets back underway this week in Bahrain for the final three days of track running ahead of the first race. The test will take place on the same circuit that will host the season-opening Bahrain Grand Prix, meaning teams will have no excuse for turning up unprepared when the new season starts on March 20.
The focus of the teams will be on gaining as deep an understanding as possible about their cars, but that won't stop observers trying to piece together a competitive picture.
Below are five key things to look out for to understand who looks competitive and analyse whether F1's new regulations have had the desired effect.