The Fisher Space pen format refill is a pressurised refill designed to allow it to write upside down and in zero gravity environments where regular ball point pens cannot operate. These refills are 8.89 cm or 3.5 inches long and 4.8 mm or 0.18 inches in diameter.
This type of refill is used in Fisher space pens and other pens that use the Fisher space pen format refill including some Sensa and Diplomat pens.
Some manufacturers such as Fisher include an adapter with their refills which increase the length to 9.84 centimetres and make them compatible with pens that use the G2 or "Parker Style" pen refill.
Some manufacturers such as Fisher include an adapter with their refills which increase the length to 9.84 centimetres and make them compatible with pens that use the G2 or "Parker Style" pen refill.
