Pilot Acroball M Colors 31810 ACC-BLKM, Black Hybrid Ink, 1.0 mm Medium Point Retractable Pen. Advanced Black Hybrid ink combines the rich vibrancy of gel ink with quick-drying ball point ink for incredibly smooth writing. Ultra-smooth, smear resistant, advanced ink. Unique textured rubber grip engineered for comfort and control. Refillable with Pilot refill P1A77297.