These fans tend to be very expensive ($25-$40) and I think a lot of HP Z800 workstations come with only 1 fan. I needed a 2nd fan since I have the hard drive bays filled and added an HBA. This was the cheapest I found for these fans and it's the last one so I though I'd share with anyone in case they also have a HP Z800 that needs the 2nd fan:
HP Z800 Workstation PCI Airflow Internal Front Case Fan Caddy 468762-001 --- USA | eBay
HP Z800 Workstation PCI Airflow Internal Front Case Fan Caddy 468762-001 --- USA | eBay
