The Fairchild combination dip pen and pencil shown above recently came to us from the wild. The seller described it as a pencil and was apparently unaware that it also had a nib -- a #6 Fairchild by all appearances original to its holder, still covered with a vivid green ink from its last usage.
Although it appears to be a standard combo with slide-out nib, twist-out pencil nozzle, and pull-out extension taper, inside there is the mechanism from a magic pencil. Pull the end knob, and the nozzle extends. Once the nozzle is fully extended, the taper can then be pulled out to its full length. Push the end knob in, and the nozzle retracts back into the barrel.
This isn't all. If the pencil nozzle is extended and the sliding ring is pushed forward to extend the nib, the ring only goes so far before hitting a stop (position shown below), after which further extension of the nib effects automatic retraction of the nozzle.
The end knob unscrews to reveal a lead reservoir, still retaining a few pieces of lead. They measure .048 inches in diameter, noting that the nozzle is clearly marked "8".