Replacement bolt action pen ink refills for Bastion pens, in a metal cartridge. They fit Bastion bolt action pens, regular and slim. Pick your ink: Standard (ballpoint) ink , black or blue: 0.7mm tip, medium point (about 1.0mm line). Black ballpoint is the ink that comes installed in Bastion pens. Gel ink , black or blue: 0.55mm tip, fine point (about 0.7mm line). Deeply pigmented gel, thinner line. Refill format: Parker-type G2 international standard, 98mm long by 5.8mm wide. The shape must match the refill shown in our product images. Some newer Parker-style refills sold as G2 have a wider body that runs almost all the way to the point, and those do not fit. Our pens need the classic Parker-type G2 shape with the tapered end toward the point. Pilot G2 refills do not fit.