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, which means that they feature all of the unique capabilities that are synonymous with Fisher products: they will write upside down - at any angle, under water, through grease, extreme temperatures (-30 to +250 degrees F), on almost any surface, three times longer than the average pen, and of course in the gravity free vacuum of space, and all of our pens are lifetime guaranteed for quality against all manufacturing defect.