Brydge is a company that makes premium external keyboards for tablets from OEMs such as Microsoft and Apple. Most recently, it has released the 'Pro', a Bluetooth accessory for the 2018 iPad of the same name. It is made of aluminium and has variants for the 11- and 12.9-inch SKUs of its corresponding device.
https://www.notebookcheck.net/Brydge-Pro-a-new-premium-Bluetooth-USB-C-keyboard-attachment-for-the-2018-iPad-Pro.423980.0.html