TWSBI's Diamond 530, 540, and 580 series aimed to revive the essence of classic writing instruments, which had become less popular due to modern advancements. The Diamond 580, a timeless fountain pen, combines traditional piston ink-filling with contemporary design, making it both nostalgic and relevant. It features a robust ink-filling system and fully disassemblable parts, allowing users to engage with the traditional aspects of fountain pen ownership.