Uniball Eye Roller Pen

The Micro 0.5mm nib is perfect for delicate, precise handwriting.

Its high quality micro rollerball combined with a unique uni-flow’ system ensures ink flows evenly to give you a smooth writing experience down to the last drop. 

• Rollerball Micro
• Smooth rollerball nib
• Consistent ink flow
• Ink barrel window

reference: https://uniball.co.uk/brands/eye/uni-ball-eye-micro-ub-150/