Verstappen heads out on track.
@Prithvi: Well it's very difficult to make a judgement like that until we have seen significant qualifying runs in Barcelona.
Ericsson is also out there on track now.
Button heads out on track again.
He might be joined by Kvyat soon, as well...
Kvyat ventures out. He and Button will be keen to accumulate more laps this afternoon.
Button's pit board suggests he will complete three more laps after dipping straight into the 1:29s.
In fact, he improves his personal best next time out, recording a 1:28.054.
Kvyat jumps ahead of Button, posting a 1:27.457.
Ericsson pits, Verstappen emerges.
Massa lowers his personal best to a 1:24.647. Kvyat improves to a 1:25.832.
Button has just broken into the 1:27s for McLaren towards the end of his current stint.
The McLaren-Honda's latest time a 1:27.872.
Massa lowers his time to 1:24.101.
The busy period has died down... Button returns to the pits and we're left with just Kvyat and Massa.
Likely some of the other teams are going to settle down for a spot of lunch soon.
It's gone silent on track. Must be lunch time.
@racer19: The nose complies with the rules and has been crash tested. They may update the nose as the season progresses.
We've had a bit of a technical issue this end, so no updates for a few minutes.
Lots of cars back out on track and Kimi is on a fastest first sector.
Button is one of the guys out on track.
@Ethan: A lot of the time its because these teams do not have too many parts yet. They certainly all have just one chassis at this point. Red Bull only had one wing on Monday and it cost them dearly...
Raikkonen lowers the benchmark again, now to a 1:21.516, and he's within six tenths off Vettel's best time.
Button dashes back to the pits for a quick stop. Massa is shaving times off his own personal best.
A few men pit so it's just Ericsson, Hamilton and Kvyat circling now
With his most recent run Button has ticked his mileage over to 31 laps. One less lap than Alonso managed yesterday.
@AM: Two more tests follow, in Barcelona (19-22 February, and Feb 26-March 1)
@suv: Hamilton had a spin earlier, which wouldn't have helped.
Track temp has nudged past 20 degrees Celsius, which gives us more representative conditions for this afternoon's running.
@kaustav: Marussia looks possible, I don't think Caterham - I think Caterham are dead and buried.
After a brief stoppage in the garage, Hamilton returns to the fray.