Uni Jetstream SXN-150-38 5P MIX GEL INK BALL PEN 0.38MM (SET OF 5)BLACK It has adopted ultra-low friction jetstream ink. It is possible to write a rich clear-cut strokes It is excellent in quick-drying of the drawn lines. It has adopted a TWINBALL mechanism for preventing INK reflux. It has adopted a SPRING TIP to prevent INK direct current. The extra lead is SXR-38