This is a refill for the Zebra Sarasa gel ink ballpoint pen, featuring vivid red ink with a 0.7mm ball diameter. When the ink in your existing Sarasa pen runs out, you can easily replace it for continued use. The specification is the JF-0.7 model; please check the compatible pen body model before purchasing to maintain precise writing quality. Due to its nature as a consumable, it is great for stocking up in offices or academies.