Your search for "C4KX-PWR-750AC" revealed the following:
Cisco C4KX-PWR-750AC-R Catalyst 4500X 750W AC F-B Airflow Switch Power Supply
SKU: NSH-3274
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
$ 43.99
• 31 in stock
Call if you need more
Cisco C4KX-PWR-750AC-F Catalyst 4500X 750W AC B-F Airflow Switch Power Supply
SKU: NSH-5554
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
$ 202.99
• Only 2 remaining
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NEW Cisco C4KX-PWR-750AC-R 750W AC Front-to-Back Airflow Switch Power Supply
SKU: NSN-1392
Condition: New
Shipping: Overnight Options
Warranty: 365 days
$ 531.99
• Only 2 remaining
Call if you need more