This 85mm frame is a full kit you can use to build, repair, or replace an 85mm quad. The base frame includes an optional thin carbon fiber frame to improve durability and rigidity. The plastic of the frame is quite rigid but also crash resistant. Comparing this to the Mobula8 frame it is much more durable and rigid. I found that you should be replacing frame far less often as well as damaging less props. The installation you can omit the carbon fiber base and save some weight, I'm not certain you really need it. My only complaint is it doesnt come with any motor screws, and the plastic+carbon fiber base requires non-standard motor screws. Overall its a nice 85mm whoop frame that I would definitely buy over the betafpv or mobula frame.