Pentel Hexreform
A narrow aluminum pen that makes an excellent EDC pen. I prefer capped pens for EDC use. The pen is super tight on the refill making it less compatible with hacked refills. No springs. Not officially available in the US.
Variants: Range of colors. Very similar to the Pentel Sterling Slim.
Refill: Pentel EnerGel. The Pelikan 338 Rollerball refill also fits, not sure if the cap seals well enough to keep the 338 from drying out.