Black ink pen.
The Pilot Acroball contains a newly created oil-based ink that has 1/5 of the viscosity (or what you could describe as \"stickiness\") of conventional oil-based inks on the market. In this sense, it is in the same category of the Uni-ball Jetstream as it targets frictionless and smooth writing performance. The unique blend of ink and lubricants allows the ball at the pen tip to rotate smoothly, creating an enjoyable, non-skip writing experience. Oil-based ink draws in satisfyingly dark lines and is also water resistant. The patent pending grip features tire-like patterns and a slightly curved shape to give a nonslip hold. Available in red, blue and black ink colors. Refills available.