HP C4900A no 940 black/yellow printhead for use in Officejet Pro 8000, Officejet Pro 8500 printers. The black/yellow print head is part of a pair used in your Officejet printer. It takes ink from the black/yellow cartridges and, using a tiny jet, applies it to the paper in small drops for fine detail. Using genuine HP technology ensures flawless printing, every time. HP print heads are designed for durability, so you only need to replace them when notified by your printer.