Stabilo COM4ball - Retractable Ballpoint Pen with Ergonomic Grip - 0.5mm - Pack of 4 Assorted Ink Colours Pack of four COM4ball Retractable Rollerball pens from Stabilo. The COM4ball features an extra long ergonomic triangular grip zone, which encourages a more comfortable hand posture as well as fatigue-free writing. Designed for lengthly writing, with its comfort grip and extremely smooth ink, the COM4ball is perfect for both students and teachers alike. The ballpoint delivers a 0.5mm line. Pack contains one of each of the following colour inked pens: Black, Blue, Red, and Green.