The Ideas:
We stock the R-4C5NP for the Ohto 2+1 Multi Pen. It is a 67mm 'D1' format refill however suitable for most multi pens and also the Minimo Tiny Pen
The R-4C5NP is unusual in being a fine needlepoint refill with waterproof ink.
The Numbers:
R-4C5NP
D1 Type
0.5mm Refills
67mm long, 2.4mm diameter.