Jetstream Colours SXN-150-05 

Retractable 0.5mm Rollerballs

0.5mm nib 

Features low viscosity ink, which gives a smooth and fluid writing

 experience.

Uni's high quality "Super Ink" is not only water and light resistant, but

 also "Tamper-Resistant", 

meaning that the ink can not be washed off using chemicals 

and solutions used by people to fraudulently modify documents.