Parker 51 Mark III and Mark IV fountain pens in Midnight Blue and Rage Red. The Mark III and Mark IV were the last two versions of the 51 pen, clip design like the 61, the Mark III with a typical plastic jewel and the Mark IV with a metal jewel. Midnight blue with gold filled made in England Mark III cap, some scratching to lower hood/upper barrel, 14K medium nib. Rage Red with Lustraloy made in USA Mark IV cap, some scratching to cap, 14K fine nib. Length 5 1/4” and 5 5/8” posted, filling mechanisms are Aerometric fill. Overall good condition, both show some wear. Pens were water tested and filled at time of listing.