Description This TWSBI stainless steel Medium replacement nib was designed for the TWSBI Vac Mini fountain pen, so that you can change different nibs to suit your mood. Just unscrew the section, push out the old nib unit and insert the new one. The TWSBI Vac Mini fountain pens are available in Smoke or Clear options. We offer Free Shipping on all orders over $59 for US customers, and for orders over $250 for our Canadian customers.