Rite in the Rain Mini Bolt Action Pen - Small but mighty, this pen is built to last. writes through MUD, Sweat, Rain, and even spilt coffee. Takes full-size cartridges. Features The triangular barrel and textured grip make for trustworthy handling. But if you drop it, don't worry... It will survive! Strong lanyard clip keeps your pen close at hand. Bolt-action feature means your pen won't accidentally open in your pocket. Replace ink with full-size cartridges. Proprietary ink and delivery system used exclusively in Rite in the Rain Pens will write without skipping in extremely wet conditions.