AirPort Extreme 6G
Apple's Airport Extreme third generation (6G) comes in a tall tower form factor.
WkiDev description: https://wikidevi.com/wiki/Apple_AirPort_Extreme_Base_Station_A1521_(ME918LL/A)
To achieve root shell, use AirPyrt and run the following commands:
python -m acp -t AirPortIP -p AirPortPassword --setprop dbug 0x3000
python -m acp -t AirPortIP -p AirPortPassword --reboot
After running these commands, your airport should reboot and you should have SSH available on TCP port 22 of your device, with password the same as your configuration passowrd.