Pocket Brush. The GFKP brush tip pen is the latest example of this technology. Employing the finest man-made bristles, the pen uses clean, convenient long-lasting refills of pigment ink that is both water and fade resistant. Leak proof fittings and measured ink flow guard against soiled clothing and unsightly manuscript. Each pen comes with 2 refill cartridges. Uses FP10 refills. 60m writing distance.