The XL 21 is a shape that is only produced in very limited numbers and only in the better grades (Except the Kinsale Line). They are hard to come by. The shape is used in the Return of Sherlock Holmes line as the Hudson and has been a St. Patrick's Day pipe on several occasions. The Army mount and Spigot stemmed versions are never around in significant numbers. I've been looking for the Rock of Cashel version for several years and can't find one anywhere. I love the way they smoke.