Lewis Hamilton and Nico Rosberg have officially unveiled the Mercedes W06 Hybrid in the Jerez pit lane on the morning of the first day of 2015 testing. The new car is the one Mercedes hopes will successfully defend the drivers' and constructors' championships won in 2014. Glimpses of the car had been seen from a filming day in Silverstone earlier this week, but the Jerez launch came ahead of Rosberg's day behind the wheel. He will alternate days with reigning world champion Hamilton for the remainder of the test. The W06's predecessor enjoyed record-breaking dominance last year, with Hamilton and Rosberg winning 16 of 19 races, and the team enters the 2015 as favourites to repeat their world championship success again.