use of indexers

private void button1_Click(object sender, RoutedEventArgs e)
    {
        Students obj = new Students();
        string FirstName = obj[0];//Getting Item using Indexers
        obj[2] = "Tim";//Modifying Item using Indexers
    }
    public class Students
    {
        List<string> students = new List<string>() { "Eric", "Bill", "Joseph" };
        public string this[int ind]
        {
            get { return students[ind]; }
            set { students[ind] = value; }
        }
    }