Extra capacity refill is designed for use with MMF Industries Jumbo Jogger Ballpoint Pens. Writes twice as long as standard refills. Writes smoothly, clearly with photocopy bank quality. Carbide ballpoints assure skip-free use. Refill will fit most desk and pocket pens. Also use in MMF Industry pens Re-Trac-To Security, Sentry and Kable Sentry pens.