Cross Fountain Pen Cartridge Ink Refills, Blue Ink Cartridges, 6 per card, (8920) Cross offers wide range of ball-point refill sizes and colors; Cross has re-invented writing instruments with jewelry-quality craftsmanship. Cross Full Perpetual Warranty Guarantee. All Cross writing instruments are unquestionably guaranteed against mechanical failure, regardless of age. Should there ever be a problem, please call a Customer Service Specialist at 1-800-282-7677. 0.5mm pencil leads; specially formulated cartridges and bottled inks, Selectip gel rolling balls, porous-points (felt tips), ball-points and document markers;