“Seamless joints are one thing. But Inventery’s Mechanical Pen doesn’t actually have any seams or joints whatsoever, instead favoring an even more minimal unibody design machined from a brass rod. To change the ink cartridge — a rollerball Schmidt P8126 capless — simply unscrew the all-brass Schmidt SKM88 Click Mechanism at the tail end. Advancing the cartridge is silky smooth, and…” (via )