using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        List<Foo> foos = new List<Foo>

        {

            new Foo { SecondsDifference = 0 },

            new Foo { SecondsDifference = 42 },

            new Foo { SecondsDifference = 1 },

        };

        var max = foos.Max(f => f.SecondsDifference);

        Console.WriteLine(max.GetType());

        Console.WriteLine(max);

    }

}

​

public class Foo

{

    public double SecondsDifference { get; set; }

}