Your search for "c9800-40-k9" revealed the following:
Rack Mount Kit 69-1937-01 C9800-40-ACC-KIT for Cisco C9800-40-K9 WLC
SKU: NSB-6613
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days
$ 132.99
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NEW Cisco C9800-40-K9 Catalyst 9800 Series 4x 10GB SFP+ Wireless Controller
SKU: NSN-3540
Condition: New
Shipping: Overnight Options
Warranty: 365 days
Cisco C9800-40-K9 40 Gbps 4x 10GB SFP+ Wireless Controller (For Up to 2000 AP's)
SKU: NSH-9571
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days