This is a genuine HP brand Duplex Unit C9101A-015
This Duplexer in working condition and works with the following printer models:

HP Officejet 6500 
HP Officejet 6000 
HP Officejet Pro 8000 
HP Officejet Pro 8500 
HP Officejet Pro 8500A 
HP Officejet J6480 
HP Officejet J6450