Uni-Ball Signo 307 - Fine Retractable Rollerball Pen - 6 Pack - Black - UMN-307 The Signo 307 expands upon the highly popular 207 with a redesigned tip, aimed to deliver dense colour and provide skip-free writing, making it perfect for situations where speed is a necessity, such as note-taking. Features Uni's high quality "Super Ink", which is not only water and light resistant, but also "Tamper-Resistant", meaning that the ink cannot be washed off using chemicals and solutions used by people to fraudulently modify documents. The 0.7mm nib delivers a fine 0.4mm line. Pack contains six Black coloured inked pens.