0.4 mm. Bold colors. Won't bleed (bold colors, that won't bleed through paper results could vary based on paper characteristic). Writes like a pen, bold like a marker! 0.4 mm fine tip provides smooth, colorful precision. Metal nib protects tip from wearing down. Perfect for notetaking, creative writing, adult coloring and journaling. Clean, crisp writing. Water-based ink makes it perfect for writing in paper. Add to your collection! Medium 1.0 mm. Fine 0.5 mm. Non-toxic. BIC Performance Policy (US and Canada): If not fully satisfied, return to bic for product replacement. AP: AMCI Art & Creative Materials Institute Certified. Conforms to ASTM D 4236. www.bicworld.com. Learn more about the bic intensity line and get inspired at www.bic.com. Made in Korea.