Most Sold Fountain Pen in the World One of the most useful fountain pens ever produced is the Parker 21. It's hard to break, never leaks, and always functions. The Parker 21 pen was the first to have its nib protected by a hood. This design decision was made to prevent ink from drying out while it was being transferred from the ink reservoir to the paper. Parker 21's body was designed to look like a jet-fighter from the side and the material used (Lucite) was the same that some wartime planes had in their nose- cone-shaped Parker 21 Green, Brushed Steel Cap, Stainless Steel Fine Nib, and Scratch-Resistant Finish Included Parker Squeeze Converter for Ink Combine with a bottle of Parker Quink Ink. Parker's Collector's Top Pick