After all these years, you can finally buy a Rotring 600 Twist Retractable ballpoint pen again, except this this time it's called the Rotring 800 Ballpoint.
Which Mechanical Pencil to Pick: Rotring 600 vs. Rotring 800 — The Gentleman Stationer
Reissue of the rOtring 600 Ballpoint - Return of an Icon — The Clicky Post
Unboxing the rOtring 800 Mechanical Pencil
DMP - Dave's Mechanical Pencils: Rotring 600 Mechanical Pencil Review
Mechanical Pencil – Gentleman Reviewer
Collection (and review in comments) : r/mechanicalpencils
Parker-Style G2
Review: Rotring 600 Ballpoint Pen
Reissue of the rOtring 600 Ballpoint - Return of an Icon — The Clicky Post