Sealed and Pressurized, Writes underwater, upside down, at any angle, from -30 degrees F,-35 degrees C to +250 degrees F,121 degrees C, over grease, 3 times longer than the average pen, is environmentally friendly. This is the replacement Cartridge for Q4 Multi-Action Space Pen or any other Multi-Ink ballpoint pen. Length is 9.8 cm, Breaks Down to 8.7 cm or 6.6 cm