Pirelli have clarified changes to the tyre rules on weekends earmarked for Sprint Qualifying, the experimental new format approved by the Formula 1 Commission on Monday.
The new format will be tried at three race weekends this season, two European events and one-non European, with an extra 100km "Sprint Qualifying" race added on the Saturday and the traditional qualifying session moved to the Friday.
The result of normal qualifying will inform the grid for Sprint Qualifying, with the result of the 100km race determining the grid for Sunday's Grand Prix.
Where the changes come in are with the tyres, and it has now been confirmed that drivers will have just five sets of soft tyres to use in Friday qualifying on Sprint Qualifying weekends.
This is different from a regular weekend, where a number of the tops teams use the medium tyre in Q2 so that they are able to start the race on the medium compound.
Drivers will then have free tyre choice during the Sprint Qualifying race and will not be required to use at least two sets of tyres.
During the Grand Prix, drivers will have free choice of tyres to start the race, but still must use at least two different compounds.