Vintage CHROMATIC 2-color ballpoint pen, silver, compatible with replacement refills

This is a two-color, silver Chromatic ballpoint pen. It's a twist-action pen, made in the USA.

The ink is dried out and won't write.
Replacement ink cartridges are needed. Compatible cartridges are 97mm long with a 2.4mm outer diameter, but these don't seem to be available domestically.
Cartridges that are 67mm long with a 2.4mm outer diameter are sold by various companies in Japan, so I've made it possible to use these by inserting a spacer into the cartridge tube. Photos 7 and 8 show one pen with the original cartridge and one with a 67mm cartridge and spacer. The twist mechanism works normally.
For the 67mm cartridge, I used a Mitsubishi SE-7 black ink cartridge that I had on hand. The spacer is made from a 2.1mm diameter nail that has been cut. The inner diameter of the tube is 2.4mm, so the spacer can be inserted and removed easily. The tip of the nail is pointed, so I think it also allows air to escape.

You will need to purchase another replacement ink cartridge. I will include one extra spacer.

There is one scratch on the exterior. See photo 3.
The twist mechanism works normally.
The original box is included, but there is some writing inside (covered with a label).

- Model Name: CHROMATIC
- Color: Silver
- Type: Two-color pen
- Accessories: Original case