Specifically made for the Fisher Bullet Space Pen, these O-rings have a notch cut out to allow for air to pass between the chamber and the outside world.

You will receive 5 O-Rings in a plastic bag as 1 item purchased.

This model will fit any any Space Pens with product numbers containing the following:
338 / 375
400 / 600
BCA

NOTE: These will NOT fit Bullet Grip Space Pens.

WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov.