Your search for "MA-ANT-20" revealed the following:

NEW Cisco Meraki MA-MNT-MR-16 Mounting Kit for MR76 MR86 Access Point

SKU: NSB-3803
Condition: New
Shipping: Overnight Options
Warranty: 365 days

Cisco Meraki ANT-10 5/7 dBi Dual Band Omni Antenna

SKU: NSB-3582
Condition: Seller refurbished
Shipping: Overnight Options
Warranty: 365 days