HP 55X (CE255X) Black High Yield Toner Cartridge for HP LaserJet Enterprise 525 P3015 HP LaserJet Pro M521. HP 55X (CE255X) toner cartridges work with: HP LaserJet Enterprise 525, P3015. HP LaserJet Pro M521. Save up to 25% with high-yield HP toner. Cartridge yield (approx.): 12,500 pages. Original HP toner cartridges produce an average of 71% more usable pages than non-HP cartridges. Ensure that your printing is right the first time and every time with HP printer toner: 55X toner. What’s in the box: 1 New Original HP 55X (CE255X) toner cartridge. Color: Black.