Multiliner SP pens have a durable aluminum barrel, refillable ink cartridge and have replaceable nibs. They are waterproof, non bleeding and have pigment-based inks. COPIC Multiliner SP pens are available in a variety of sizes for all your creative needs. Refill ink cartridge A is for pen sizes .03mm, .05mm and 1mm. Refill ink cartridge B is for pen sizes .2mm, .25mm, .3mm, .35mm, .5mm, .7mm and Brush