This .50 caliber bullet cartridge pen kit will make a great gift for any outdoors man or a military enthusiast. First developed for the Browning, a .50 caliber machine gun in the late 1910’s, the cartridge used in this kit is commonly used in the military. Utilizing an authentic .50 caliber once-fired brass cartridge, turns this into a one-of-a-kind pen. Overall size of the bullet pen is 5-1/2″ to 6-3/8″, using a Cross type refill.