Schmidt Mini Ballpoint Refill, Red Medium International Size D1 German made Mini ballpoint refill in Red, medium point. Made in Germany by Schmidt and packaged in the US under the Private Reserve Ink name. Fits all pens using the international size D1 (mini) refill. Approximately 2-5/8 long. Schmidt part number 635. Partial list of pens that use this refill: Cross Multi-Function Pens, Franklin Covey Hinsdale, Kaweco Sport and Liliput, Lamy Multi-Pens, Monteverde Tool Pen, Parker Executive Quattro, Retro 51 Tornado Elite & Touch, Rotring Multi-Pens (Duo, Trio, Quattro), Worther Shorty Ballpoint, and any other pen taking the international-size D1 mini ballpoint refill.