The purple-striped ultrasoft tyre has once again proved very popular with teams ahead of the Singapore Grand Prix.
However, there are split strategies at Mercedes and Ferrari with alternative approaches taken for title rivals Lewis Hamilton and Sebastian Vettel.
Hamilton has been allocated an extra set of soft tyres with team-mate Valtteri Bottas taken on pne more set of red-striped supers.
Vettel, meanwhile, also has two lots of soft tyres to play with, but just one set of supers to make room for 10 sets of ultrasoft tyre. In comparision, Kimi Raikkonen also has 10 sets of ultras, but one set of supersofts and an extra pair of softs.
Bar Mercedes, and Toro Rosso's Carlos Sainz, the rest of the field have all opted for 10 sets of ultras.