Your search for "c3kx-ps-blank" revealed the following:
Cisco C3KX-PS-BLANK Power Supply Blank Module for 3750X and 3560X Series
SKU: NSH-3036
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
$ 12.99
• 50 in stock
Call if you need more
NEW Cisco C3KX-PS-BLANK Power Supply Blank Module for 3750X and 3560X Series
SKU: NSN-9458
Condition: New
Shipping: Overnight Options
Warranty: 365 days