This green and yellow ebonite fountain pen is the Esterbrook Model J. It comes with gold-plated trim and a gold-plated JoWo #6 stainless steel nib. A modern take on a vintage classic. It fills via standard international cartridge/converter (included). 
 
From Esterbrook:
Introducing the Esterbrook Model J - a timeless masterpiece that gracefully blends vintage charm with modern ingenuity. Crafted with exquisite ebonite from Germany, this pen showcases a seamless fusion of tradition and innovation. Its iconic design, inspired by the beloved 1950's vintage model, pays homage to Esterbrook's rich heritage.

Equipped with a Jowo size 6 gold plated nib, available in various sizes, including custom options, this pen promises an exceptional writing performance. Delight in the subtle yet distinctive barrel engraving, adorned with the R.Esterbrook signature logo, while the grip section ensures extended writing comfort.

Encased in slide premium packaging, complete with a vintage-inspired sleeve adorned with Esterbrook factory imagery, the Esterbrook Model J is a timeless treasure waiting to grace your collection.