It's never a bad idea to have some extra pen refills. The compact ink cartridge in the drafting series of pens means the refills are smaller and run out a bit faster than a standard refill. A small price for style and precision.

A refill for Perfection Bullet Ballpoint Pens and Bullet Perfection light Ballpoint Pens.  

• 4C (D1) Needle Tip Refill
• 0.5mm nib
• Black Ink