Liverpool manager Jurgen Klopp praised his defence and said his back four planned to stay at the Premier League club for a long time.
Led by Virgil van Dijk, Liverpool have conceded just 19 goals in 32 league games this season, putting them in title contention.
Van Dijk, 27, Andy Robertson, 25, Trent Alexander-Arnold, 20, and Joel Matip, 27, have played the majority of Premier League games for Liverpool, while Joe Gomez is only 21.
The age profile of his back four pleases Klopp, who hopes his defenders remain at Anfield.
"They have a long career ahead, which is cool," he said ahead of Friday's trip to Southampton.
"And how it looks at the moment is that they want to spend the majority of their careers here, which is cool as well."
While Van Dijk cost Liverpool a reported £75million, Robertson arrived for £8m, Matip on a free and Alexander-Arnold through the youth system.
Klopp, whose team are a point behind league leaders Manchester City, said the cost was irrelevant.
"It is probably not the most expensive defence in the world but it is a proper one, a really proper one," he said.
"Wherever good players are coming from, wherever they are raised, wherever the dream started, they are welcome here at Liverpool."
Liverpool have conceded just 19 goals through 32 matches in the Premier League, the best record in the league and two goals better than Manchester City.
Friday's contest comes ahead of a tough stretch for Klopp's club that should test his back line to the fullest.
The Reds have just six matches left in their Premier League season as they look to chase down an elusive title.