Features: Long-Lasting and Replaceable: Each pack includes 50/100pcs of 3. 4mm replaceable ink sacs, ensuring a continuous flow of ink for your fountain pen. With a universal design, these ink refills can be used with various fountain pens. Quality Ink: The fountain pen refills are formulated with long-lasting color and good fluidity, providing a smooth writing experience. Whether you're studying, working in the office, or creating cards and writing letters, these refills deliver vibrant and consistent ink flow. Convenient Fountain Pen Replacement: These refills serve as excellent replacements for worn-out ink sacs in fountain pens. Simply replace the old sac with a new one to restore your pen's functionality and extend its lifespan. This makes them essential student stationery accessories. Versatile Usage: Suitable for various writing tasks, these refills are perfect for studying, working in the office, and even for personal hobbies like making cards and writing letters. They offer a reliable and consistent ink supply, allowing you to focus on your tasks without interruptions. Easy to Use: The 3. 4mm universal ink refills are designed for effortless installation. Simply remove the old ink sac and replace it with a new one. This user-friendly feature ensures a hassle-free experience, making these refills suitable for both beginners and experienced fountain pen users. Specifications: Material: Ink Length: 50mm Include: Choice1/2: 50pcs Ink Refills OR Choice3/4: 100pcs Ink Refills