Just finished making this custom Rotring Quattro pencil w/ .3mm, .5mm & 2x .7mm. Took some work to get 4 mechanisms to all fit and function, proud of how it turned out :
Rotring Quattro Executive Multi-pen | Unsharpen
rotringの4in1多機能ボールペンが細身で使いやすくておすすめ - 男40代の秘密基地
筆倉】 德國 紅環 rOtring Quattro Pen 4-in-1 四合一多功能筆 | Yahoo奇摩拍賣
Rotring Quattro Pen in Matte Black (black, 0.5 mm, highlighter, Input) R 503 701
Rotring Trio Multi-pen | Unsharpen
Rotring Quattro Pen in Matte Black (pen. 5 mm pencil, highlighter, stylus)
Rotring Quattro Matte Black Black & Red Pen, 0.5 Pencil, & Hiliter New 45695
Rotring ARTOS Quattro 0.7 Pencil Ballpoint Pen Red Ring | Etsy