Pencils will work great on Rite in the Rain but sometimes you just need a pen. This easy-to-find, All-Weather Pen writes on wet paper and upside down, the pressurized ink cartridge performs in temperatures from -30F to 250F. The ink won't leak, evaporate or blow up in your pocket! 5 1/4" long, with a Barrel Diameter of 3/8". Black ink.