● “Acro Ink” oil-based ink for smooth, thick writing ● “Acro Ink” has approximately 1/5 the viscosity of our oil-based ink. ●Acro Ink has about 1/5 the viscosity of our oil-based ink. ●Acro Ink also contains a lubricant that reduces the frictional resistance of the ball at the nib, resulting in smoother rotation and smoother, darker strokes. The ink is also lubricated with a lubricant that reduces the frictional resistance of the ball at the nib. Since its launch in 1991, the Dr. Grip pen has made history as the standard for “fatigue-resistant pens. The Dr. Grip is a multi-functional writing instrument that is thoroughly usable and inherits the spirit of Dr. Grip. The four-color ballpoint pen and mechanical pencil ●You can easily coordinate your handwriting by using different ballpoint pens for different situations. With the mechanical pencil, you can quickly write and erase your thoughts and feelings without hesitation.