This is a compatible HP Q2624X toner cartridge. Used in HP Laserjet 1150, this HP Q2624X cartridge is 100% compatible to the original Q2624X toner cartridge it replaces. Can replace Q2624a or Q2624X. The difference between the "a" and the "x" is that the Q2624A has a page yield of 2500 pages, and the Q2624X has a 4,000 page yeild. This is 100% compatible to the Q2624X (higher capacity) toner cartridge