Pentel Super Hi-Polymer Refill, 0.5mm, Fine, F, (C505-F)

For paper surfaces, formulated with polymer resin bonded to carbon and graphite particles that never need sharpening. These leads break less, last longer, write smoother, and produce dense black lines that resist smearing and fading. Use 0.3mm extra-fine lead for small details, 0.5mm fine lead for accounting and general writing, 0.7mm medium lead for students, and 0.9mm thick lead for drawing.