The Uniball Signo RT1 offers an exceptionally smooth writing experience for a 0.38 mm pen. Its tip design is edgeless and rounded, eliminating undue friction with the page. The pigment-based gel ink lays down a smooth, clear, sharp line and is waterproof, fade-resistant, feather-resistant, fraud-resistant and archival-quality. The Signo RT1’s body shape is designed to further enhance the feeling of smoothness: the comfortable rubberised grip melds stylishly into the barrel and the pocket clip attaches seamlessly to the push clip. The semi-transparent coloured barrel allows a glimpse of the ink, showing you when the ink is running low. Refills: Uni UMR-83 Gel Pen Refill - 0.38 mm .