The Fisher Space Pen B4 Shuttle Space Pen is the same pen as the Fisher CH4 but with a black grid engraved into the exterior. Sometimes known as the “Fisher Grid Pen” or more officially as the “Black Grid Design Shuttle Space Pen,” the B4 is an upgrade of the standard CH4. The grid on the exterior not only adds grip to the pen but looks great. The pen is backed by Fisher’s lifetime warranty.