Class grouping in C# : My question seems weird and maybe not understandable. Sorry for my bad english.

I have 3 classes called SmallStick, LongStick and OldShovel.
Now I want a list of these classes in one class.

Here are sample codes:

My "Item" Classes:

      public class SmallStick : IItem
      {
        public string ItemName = "Small Stick";
        public ItemType ItemType = ItemType.WEAPON;
      }
      public class LongStick : IItem
      {
        public string ItemName = "Long Stick";
        public ItemType ItemType = ItemType.WEAPON;
      }
      public class OldShovel : IItem
      {
        public string ItemName = "Old Shovel";
        public ItemType ItemType = ItemType.TOOL;
      }

Now I want a class like this:

    public class Inventory
    {
      List</*Class that represents every kind of these Items above*/> Items = new 
      List</*Class that repre...*/>();
    }

Please don't flag or downvote my question.