Refill for Rotating Head (Classic scriber)
Fisher Space Pen Model PSGB-20
"Plotter Super Giant Bold 2.0 inches long."
Does NOT fit the Classic Scriber itself (use Lumocolor-F for that) . . . . this refill fits ONLY the optional Rotating Heads for Classic.
Also can be purchased from other places, including from Fisher Space Pen Company in USA. See your Classic Scriber User's Manual (pdf) for more sources.
PSGM-20 will fit into the rotating head, too—but it has a medium nib. I prefer the Bold nib.
The PSG refills are available in many lengths. But ONLY the 2.0 inch length can be used in the Classic Scriber's Rotating Heads.