Pilot Ballpoint Pen Refills, 10 pieces Acro Ink BRFV 10EF-B 0.5 Extra Fine Oil-based Black New, Unused Regular Price: 100 yen each (excluding tax) [Product Description] Type: Oil-based ballpoint pen refill Ball diameter: 0.5mm Ink color: Black (B) Size: Total length 115.0 x maximum diameter 4.0mm These are 0.5mm ballpoint pen refills with Acro Ink, compatible with oil-based ballpoint pens such as Acroball, Acro 300, Acro 1000, and Iro Milly. Thank you for viewing. I no longer have a use for these, so I'm offering them to someone who will. Although they are new and unused, they have been stored at home, so please understand this before purchasing.