The size of the tip ranges from; 0.18 mm to 1.5 mm, which depends on the usage of the pen. You may go for a smaller size tip for finer and precise strokes, as opposed to a bigger sized tip for thicker and bolder strokes for emphasis. The finer the tip, the less smudges are likely to occur.
Different colors are available in packs, and the barrel of the pen is refillable. Different shades and tints give documents a professional look when used to sign signatures.
Gel pens are not expensive, considering their usefulness. As of October 2010, the price for a gel pen ranged from $3.99 to $16.99.