The TWSBI Classic has recently come out with a revised piston knob which now makes the pen postable. TWSBI is offering these replacement knobs available for a small fee. In this video I show you how easy it is to replace the old piston knob with the new one. All you need is the new knob and the wrench included with your pen. You can also use this technique to remove the piston and clean your pen.
TWSBI Classic
Ink it Up!
Brian & Lisa