After years of adoration by the light industrial and construction industries, Fisher Space ballpoint pen brings to you the most durable and reliable writing instrument on any job site. The Cap-O-Matic line utilizes cap activation to extend and retract the point, and each carries a gas pressurized PR style ink refill cartridge. They will write upside down, at any angle, under water, through grease, in extreme temperatures of minus 30 to plus 250 degrees F, on almost any surface, three times longer than the average pen, and, of course, in the gravity free vacuum of space.