Pentel Sterling Slim
Feels like nickel coated brass pen with sections that are coated in real silver. The almost brown sections are the tarnished silver that has changed over time, starting out just a touch more grey than the bright furniture. Snap cap that has the same action on both ends. Excellent pocket, bag, and planner pen. Not my first pick for all day writing with the narrow metal grip.
Variants: Only the one. Very similar to the Hexreform but this one is round.
Refill: Pentel EnerGel. The pen is very tight on the refill. It doesn’t have any springs. I’d expect difficulty hacking other refills in this pen short of maybe Zebra or retractable Uni gel refills.