Low-tech Skilcraft pens endure in a high-tech world
The original design — brass ink tube, plastic barrel not shorter than 4 5/8 inches, ball of 94 percent tungsten carbide and 6 percent cobalt — has changed little over the decades... The original 16-page specifications for the pen are still in force: It must be able to write continuously for a mile and in temperatures up to 160 degrees and down to 40 degrees below zero.