This is a pack of three refills for the Pilot FriXion Ball Slim gel ink pen or Pilot FriXion Ball 3 3 Color gel ink multi pen. It is interchangeable with Pilot's FriXion multi pen refills (model number LFBTRF30EF).
Thank goodness there are refills!!!!! the only downside is that the refills run
out very fast, and as a college student I write a lot. Glad they come in packs
of three (I usually buy 2 at a time) and I love that they are great erasable