This is a Parker Duofold Vacumatic Ingenue in striped Blue Laidtone celluloid, a combination of blue, silver, and black strips, which are translucent in the barrel so the user can check the ink level. Ingenue models were also available in striped Maroon and Green. This 4 3/4 inch long pen is date coded 1940, when the striped Duofolds were introduced. They were phased out in 1948. The clip style carries over from the previous Challenger and "toothbrush" Duofold. The Blue Diamond on the clip indicated Parker's "Life Guarantee Contract" against everything except loss or intentional damage. Note the V style unhallmarked gold nib. The plunger is the clear plastic type. They sold for $8.75 and the matching pencil was $4.00.