While the pencil does work the key here is the roller. This pen uses the The Pentel RMJ8 refill or as it is called the jumbo refill. I havs bought so many of these just to have the ball break or no ink left. I found a few that work so I pulled the matching pencil out and put them in the daily rotation.
Here is the RMJ8 refill. Have any for sale let me know. Pentel does not make the Jumbo anymore. Add these great pens and pencils to your collection.