Your search for "c3kx-nm-10gt" revealed the following:
Cisco C3KX-NM-10GT 2x 10GB RJ45 Switch Module for Catalyst 3750X and 3560X
SKU: NSH-1223
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
$ 133.99
• 5 in stock
Call if you need more
NEW Cisco C3KX-NM-10GT 2x 10GB RJ45 Switch Module for Catalyst 3750X and 3560X
SKU: NSN-1019
Condition: New
Shipping: Overnight Options
Warranty: 365 days
$ 229.99
• Only 2 remaining
Call if you need more