The deep wells in the cylinders and the square sleeves are painstakingly drilled out from a solid block with a gun drill. This machine uses high pressure oil pumped to the cutting edge of a specialized bit to slowly drill out a perfectly straight and deep well. The clean and smooth cylindrical pen slides neatly into its sleeve, held in by a magnet once in its final position. You’ll note a slight popping sound when removing it from its sheath—the effect of high tolerances creating a pneumatic seal, much like a piston. There is no visible branding on the surface of Pen Type-A.