Mercedes, Force India and Toro Rosso are set to become the latest teams to trial the 'Halo' cockpit protection device during free practice for the Belgian Grand Prix.

With the controversial device deferred to a 2018 introduction after it was considered it hadn't received enough real-time track testing to rush a 2017 debut, the FIA is pushing ahead with development programme.

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Indeed, having urged teams to assist in development by testing the device during FP1 sessions to the end of the season, Mercedes will run the 'Halo' in FP1, while Force India and Toro Rosso have since confirmed it will follow suit.

So far only Ferrari and Red Bull have fitted to Halo to its cars this year, while it has only completed a handful of slow installation laps at the Circuit de Catalunya and Silverstone.

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With Hulkenberg set to use the Halo in Belgium, the German admits he will only be giving it a brief outing in FP1.

"To get a proper read and understanding you need to run it longer than that, but tomorrow is only a first impression and a first read so there is more to come later in the year.

The device is also yet to run in wet conditions with weather expected to remain very sunny at Spa-Francorchamps this weekend.