HP 503A (Q7581A) Cyan Toner Cartridge for HP Color LaserJet 3800 CP3505. HP 503A (Q7581A) toner cartridges work with: HP Color LaserJet 3800, CP3505. Original HP toner cartridges produce an average of 71% more usable pages than non-HP cartridges. Cartridge yield (approx.): 6,000 pages. 503A toner is designed to work with your HP printer for high quality, reliable results every print. Ensure that your printing is right the first time and every time with HP printer toner: 503A toner. What’s in the Box: 1 New Original HP 503A (Q7581A) toner cartridge. Color: Cyan.