Ballograf refills are tested to write almost 30,000 feet without smearing or clogging. The Original Ballograf Refill ("Austenit" style) fits Epoca, Rondo, Nordica, and Opus pens by Ballograf. Archival ink. 3.75" (95 mm) long. Specify BLUE or BLACK ink, and FINE or MEDIUM point. (Sold singly.)