This is a Merz & Krell piston fill pen in blue etched celluloid from the 1950s. It is similar to celluloid used by Conklin in the 1930s, though Conklin did not use this blue. The large ink view window in the barrel shows a black and clear spiral pattern. The piston knob is accessed by removing the black end cap. The Number 2 stainless steel semi flex nib originally was lightly gold plated, but the plating is polished off and now shows bright stainless steel. There are no makers marks on the 4 13/16 inch long pen other than nib maker Degussa's half eclipsed sun stamping on the nib.