Features: European Standard spirals inks converter with vacuum sealed cartridge ensures leak proof performances and broad compatibility across major fountain pen brands, featuring tool frees installation in seconds for effortless inks refills.Engineered with a metal reinforced collar and precisions spirals mechanism, this converter combines robust construction with smooth inks flows control, ideal for consistent writing pressure and long term reliability.Perfect for students, handwriting enthusiasts, business professional, and frequent travelers seeking safe, mess frees inks replenishment solution for daily journals, official documents, or artistic projects.Optimize productivity during lectures, client meetings, or creative meeting with its quick load design and anti drying technology that maintains optimal inks viscosity across climates.Crafted from quality materials including recyclable plastics and corrosions resistant metal components, this converter delivers light weight portability while aligning with sustainable lifestyle preferences.Specifications: Materials: Plastic+MetalColor: As The Picture ShowsCalibers: 2.6/3.4 (Optional)3.4 Size: approx.7cm/2.75in(More Size Detail,See Picture.)Package Includes: 10Pcs Pen Convertersnote:allow 1-2cm error due to manual measurement.