So, you want to buy a vintage rOtring? A "guide" of sorts. — The Clicky Post
Amazon.com: Rotring 600 3-in-1 Multicolor Pen and Mechanical Pencil, Switches Between 2 Ballpoint Pen Fine Point Tips (Black and Red Ink) and 1 Mechanical Pencil Tip (0.5mm Lead), Black Barrel : Everything Else
Amazon.com : ROTRING 2121116 Lot Ring 600 3-in-1 Black Twist Type : Office Products
ROTRING 600 - AUGENWESEN
Rotring 600 Series 3 in 1 Multi Pen - Camouflage Green Brass Body – Art&Stationery
Rotring Trio Multi-pen | Unsharpen
Vintage Rotring 600 Newton Trio 3 in 1 Combo in Near Mint Condition | eBay