Refills for the teachers pens (and mini-pens) can be purchased from PSI, or anyone who carries the PSI line. PKMINI-R5 (black) or PKMINI-R5R (red) - $4.50 for a 5-pack (from PSI). The tip is not the same as a cross-style refill and I would not attempt to cut one down even if it were (I can imagine the mess).