This is a Parker Vacumatic Junior in Transparent Grey date coded 1934. This 4 3/4 inch long pen has large clear elements in the barrel so the user could check the ink level. These early Vacumatics have a lockdown-filler unit that required the user to remove the blind cap and press and turn the filler knob that unlocked and extended the spring loaded plunger so the pen could be filled. Note the unhallmarked 1934 date coded Parker Vacumatic stamped gold nib nib that pre-dates the Arrow nibs. These pens sold for $5.00.