Почему не работает (base)?

{
class Caps : Inventory_for_box
{
    public int AgeGroup { get; set; }
    public string Type { get; set; }
    public override string AllInventory()
    {
        return base.AllInventory() + "Age group" + this.AgeGroup + "Type" + this.Type;
    }
    public Caps(string name, int prise, string manufacture, int number, string color, int ageGroup,string type):base( name,  prise,  manufacture,  number,  color)
    {
        AgeGroup = ageGroup;
        Type = type;
    }
}

}