This Cartridge Bullet Twist Pen kit replicates a 30.06 rifle cartridge. This is an extremely easy kit to make using a single tube. This kit uses a Parker™ style ball point refill or gel refill and uses the high grade double twist mechanism. This kit also comes with the premium rifle clip. This kit will make an excellent gift for a hunting or shooting enthusiast. These kits have the Bolt Action Rifle Clip. The M-16 Clip is sold separately.