|Belgian Grand Prix|
|Dates: 26-28 August. Venue: Spa-Francorchamps|
|BBC coverage: Race commentary - Sunday 28 August (build-up on BBC Radio 5 live from 12:55 BST, race starts at 13:00). Live text and radio updates of all practice sessions, qualifying and the race on the BBC Sport website|
Nico Rosberg says his test of the 'halo' head protection system at the Belgian Grand Prix was "a success".
The Mercedes driver ran the device, which is to be introduced into F1 in 2018, for about half the first practice session and set the fastest time with it on the car.
One concern was whether the 'halo' would affect visibility on steep hills, but Rosberg said that was not the case.
"They have done a great job because it doesn't disturb me at all," he said.
"It just increases the safety a lot. I know it's not nice-looking from the outside. It doesn't make the cars prettier. But if it is such a big step in safety, then I think it is a good thing."
Governing body the FIA had intended to introduce the 'halo' next year but the strategy group of leading bosses voted last month to delay it by a year so further research could be conducted.
FIA F1 director Charlie Whiting wants most of the teams and drivers to run with it during a practice session over the remainder of this year.
Spa was considered to be a good test of its effect on visibility because there are several hilly sections, most noticeably the famous Eau Rouge swerves.
These are taken at more than 180mph and feature a downhill entry, a compression and then a steep rise over a crest.
Rosberg said he had not even noticed the 'halo' was on the car when going through Eau Rouge flat out.
"You don't even notice the top part," he said, adding that he felt the top of the halo could even be made lower if necessary without impinging on visibility.
Toro Rosso's Carlos Sainz also reported no visibility problems at Eau Rouge.
But Red Bull's Daniel Ricciardo and Force India's Nico Hulkenberg, who also ran with the 'halo' in the session, gave more mixed reviews.
Ricciardo - like Rosberg, a strong supporter of the plans for increased head protection - said it was "not too bad", but added: "It's definitely a work in progress."
Hulkenberg, who has been more equivocal about the 'halo', said: "It was a weird feeling, and to have something there which limits you was obviously a new experience.
"I have to say visibility wasn't too bad, I don't think that was an issue. It will take time to get used to."
He added that he had done only one lap with it, which was "nowhere near enough to properly understand".