Red Bull boss Christian Horner believes that his test drivers will play an important part in boosting the team's performance as Formula 1 sees significant changes in regulations next year.
The constructors' champions have confirmed former Toro Rosso racer Sebastien Buemi and Antonio Felix da Costa as their test drivers, and Horner suggests that their contribution will be vital.
He said: "Next year sees the biggest change to the Formula 1 regulations for some time and the return of multiple in-season tests. To therefore be able to call on two such capable drivers is of huge benefit to the team."
Red Bull also signed Australian Daniel Ricciardo to partner Sebastian Vettel in 2014.
