The pressure bar has an attached stud. This stud is shielded inside a short metal tube/collar to prevent accidental pressing of the stud. Any matchstick or pencil point would suffice to press the stud. However, the cap has a recessed stick inside wider circular depression in the cap. The top of the cap can then be placed over the stud and protective collar to press the stud. This is conceptually much like the Wiedlich pen, but in this case the stick on the cap is recessed, protected, and not so visibly awkward. [photo by Peter Sacopulos, from The Pennant, Fall 2024]
