What is the string tension of Roger Federer's racquet?

Roger Federer's racquet has 24 - 28 kg (50-60 lbs) recommended tension, depending on his opponent, court conditions, weather, altitude, humidity, etc.

For matches, he (as well as other players) will have several racquets in his bag with varied tensions. Like racquet choice, string tension is a very personal decision.

He has mentioned how on hard courts and grass courts (although opponents can cause this to vary), he prefers his string tension to be higher, which offers more control (grass and hard courts are the fastest courts).