5pcs/pack Fine Cross Style Blue And Black Ink 0.5mm Medium Nib Ballpoint Pen Refills Writing Smooth Ballpoint Pen Refills - Ballpoint Pens - AliExpress
Cross Fountain Pen Ink Cartridge Black BLUE Blue/Black Washable Blue x12 | eBay
Office Depot
2 Packs - Cross Fountain Pen Cartridge Ink Refills, Black Ink 6 per card (8921) | eBay