Enhancing your writing with this fountain pen inks piston converter, must have accessory for maintaining the durability and functionality of your favorite fountain pen, calligraphy inks pen Crafted from ABS and metal, this refillable twist action inks converter features rotating knot that ensures easy and quick inks refills while leaks seamless writing with our 2.6mm / 3.4mm Bore Diameter Rotating Fountain Pen Inks Converter, fit on various fountain pen, retractable inks pen, press fountain pen, retractable fountain pen Widely used for schools, offices, meeting, lecture report, and homeschooling, allowing you to refill your fountain pen, ensuring uninterrupted writing Suitable for students, teacher, workers, business professional, artist, and fountain pen enthusiasts who demand convenienct replaceable fountain pen inks converter for daily writing and signing tasks