The Esterbrook M2 fountain pen was designed by Henry Dreyfuss. One of its most distinctive features is the V-shaped notch on the top of the cap. It is a lesser-known model among Esterbrook pens, and its pump-filling mechanism is also rare. Its greatest advantage is its compatibility with 32 different Esterbrook screw-in nib units. The pen is in perfect condition and can be tested upon pickup.