Your search for "RCKMNT-1RU-2KX" revealed the following:
NEW For Cisco NT-RCKMNT-1RU-2KX Catalyst 2960X Series Switch Rack Mount Kit
SKU: NSB-6489
Condition: New
Shipping: Overnight Options
Warranty: 365 days
$ 16.99
• 4 in stock
Call if you need more
NEW Cisco RCKMNT-1RU-2KX Catalyst 2960X Series Switch Rack Mount Kit
SKU: NSH-5981
Condition: New
Shipping: Overnight Options
Warranty: 365 days
$ 18.99
• Only 2 remaining
Call if you need more