BIC Cristal Pens have a medium 1.0mm ball with a line width of 0.4mm which is cased inside a clear hexagonal barrel, for comfortable handling. The coloured lid and plug, aswell as the visible ink make it easy to see which colour pen you're picking up, this comes in handy as the Cristal range come in 4 varieties, Black, Red, Blue and Green.Environmental benefitsLong lasting product: up to 2 kilometers writing lengthLight: designed and manufactured with just the right amount of raw materialsPVC free product French ecolabel NF Environnement (NF 400) for the refillable model (in 50-box, sold on catalogue or at stationers)"