ever worry about lead breaking again! The DelGuard pencil uses an innovative mechanism developed by Zebra that prevents lead breakage. The secret is in the moving parts inside the pencil tip and grip area. How exactly does it work? If you apply vertical pressure to the lead as you write, a spring inside the pencil absorbs the pressure and allows the lead to retract a little so that it's protected by the guide pipe. If you apply diagonal pressure, the guide pipe and tip which guard the lead extend further out, thus protecting more of the lead.