How to extend an existing ZenWIFI XT8 Mesh

[q5dxhjhgxv]

Hi - I would like to extend my existing ZenWIFI XT8 Mesh (2x XT8) with another Asus unit for my garage, as reception is very weak there. Do I have to get another XT8 or can i use any other (smaller / cheaper) Asus mesh unit to extend the existing one ? I could not find any compatibility list online. Any help would be greatly appreciated. 

[jzchen]

Any AiMesh capable unit should work.  Emphasis on the "should".