var numbers = new[] {1,2,3,4,5,6,7,8,9,10};
var someNumbers = numbers.Where(n => n < 6);

Console.WriteLine(someNumbers.GetType().Name);
//WhereArrayIterator`1

var someNumbersList = someNumbers.ToList();

Console.WriteLine(
    someNumbersList.GetType().Name + " - " +
    someNumbersList.GetType().GetGenericArguments()[0].Name);
//List`1 - Int32