Able to withstand extreme temperatures, altitudes, and environments, this is the same style pen used on Mt. Everest when other units failed to function. Wielded by experienced hikers and mountain climbers when scaling 29,000', the pen’s thixotropic ink is sealed in a pressurized cartridge that enables it to write in temperatures from -30º F to 250º F, underwater, and at any angle—even upside down. Created by Fisher Space Pen, it has an ultra-hard tungsten carbide ball that writes a medium line in black ink and lasts up to three times longer than ordinary ballpoints. The pen has a sleek anodized aluminum barrel and a carabiner clip for securing to a backpack, belt loop, or climbing gear. With a rubber grip and cap with an attached key ring.