. Unique formulation design， the cover is open four hours， the ink does not dry out. PP material clip design appearance， so more convenient to carry， excellent air tightness and high-capacity ink to ensure that long-term use and preservation. Environmentally friendly non-toxic materials， writing no pungent smell of ink. When covering the ink and printing fonts， font will not open， and difficult to penetrate， keeping a clean page file . 1mm ~ 4mm pen width， in line with the mainstream of modern use