The unique bolt action shape allows for one fluid motion to advance or retract the refill. Because the surfaces of both the interior part and the inside surface have been carefully machined to be extra smooth, the action feels amazingly satisfying. If there\’s one pen that we recommend to new customers, it\’s the Bolt Action. All-metal, durable bolt action mechanism Three lengths: Standard, Short, Mini Available in Titanium, Copper, Bronze, and Zirconium Stainless Steel deep-carry clip One of the few metallic elements with a natural color other than gray or silver. Naturally antimicrobial, copper will patina and darken with time and use.