Your search for "AIR-CT3504" revealed the following:

Cisco AIR-CT3504-K9 4x 1GB RJ45 Wireless LAN Controller for up to 150 AP's

SKU: NSH-6760
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days

$ 203.99

$ 306.99

• Only 2 remaining
Call if you need more

Cisco AIR-CT3504-RMNT 3504 Wireless Controller Series Rack Mount Tray

SKU: NSH-7741
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days