Uni-Ball Magik Girl 0.7 Erasable Rollerball Gel Pens x 12 Blue ink like Frixion
The Uni - Ball Magik like the Pilot Frixion, uses Thermo Sensitive Ink which can be erased by heat, you write, you erase, you are then ready straight away to write again, no waiting for Tipp-Ex to dry etc.