Original Bead Pens Metal Customizable Lampwork Craft, Writing Tool (Blue) All BeadPens are entirely constructed of metal. The BeadPens have an extremely fine anodized finish. The overall length of each BeadPen is 6 inches. The usuable length of the rod for placement of beads is 2 1/2 inches. The mandrel (rod) is 3/32 inch which fits most lampwork beads.