Uniball SigNo UM120 with Gel Ink Roller Ball 0.4mm Line, 0.7mm Ball (Blue, Black Red, Green) Uni-ball Signo UM-120 Gel Pen Color Black, Green, Blue, Red The uni-ball Signo UM-120 gel pen is a wonderful creative tool for writing and drawing. Its paint-like opaque line looks powerful on paper and card of all colors. Its fine nib gives you precision and finesse lovely for decorative script, illustration or simple doodles.