This is an interesting Fairchild combo as the pencil actually works like a magic pencil whereas most of the old combos use a twist action to extend/repel. The nib says “Leroy W Fairchild New York 4” and the inner pencil barrel is stamped “Fairchild” on one side and “Patented June 22, 1869” on the other. What makes this one rather odd is that the patent date and design was actually filed by John Rauch, not Fairchild (patent # 91665). According to Jonathan Veley, Rauch and Mabie Todd both had examples of this design but this is the only Fairchild I’ve seen where the pencil protrudes out the opposite end.
"Fairchild", "Patented June 22, 1869", Nib is stamped "Leroy W Fairchild New York 4"