It is a multicolor type Acroball that can be used wisely by color-coding notebooks and documents. It is convenient for those who required to write on tiny spaces. This series all refills are in 0.3mm, but it can be replaced with 0.5mm and 0.7mm refill. Refill: Pilot BVRF Acro Ink Multifucntion Refill. Each pen comes with black, blue and red ink.