3mm at the at the Widest point of the ball. By varying downward pressure a difference line thickness can be produced. (Max. width 3mm)
Solid ball on tip. All purpose writing nib. Burns a trench like impression. The T99.030 is excellent for general purpose work. Straight lines, curves, tight curves and circles, writing and colouring in. Very useful for burning stipples. Holds heat well giving consistent burns. Needs a bit of extra heating and cooling time over most tips.