Can be used as a quick-use pen or easily converted into a full-size pen. Replaceable pressurized cartridge allows for writing at any angle, in extreme temperatures, and at any altitude. Split ring attaches to key chains, backpacks, and more for ultimate accessibility. Waterproof blue ink. To use as a quick-use pen, simply pull the pen out of the aluminum barrel to use in the quick-use mode. To convert to a full-size pen, unscrew the barrel from the split ring, unscrew the cap from the quick-use pen, screw the quick-use section into the barrel and replace the cap on the open end.