Here is the mounting system I made to install it.
ARB gives you nothing to mount it except the 4 stainless bolts and nylock nuts that fit the channels in the extruded aluminum back .
The smaller 55" Tuff Stuff awning I have on back included the 2 stainless steel L brackets I used to mount the ARB awning.
Like a lot of the Roof Top Tents you see, both ARB and Tuff Stuff use essentially the same design for their awnings. So both awnings have the same extruded aluminum back you see in the photo. They have the same channel spacing, so the Tuff Stuff L brackets worked perfect for the heavier/larger ARB awning.
I added the u-bolts you see. They are flush mounted/bolted to the L bracket from the bottom using a bevel head screw then covered with thin black foam rubber(for grip on a round crossbar) and a nylock nut on top to secure each u-bolt flat bar to the L bracket. I also put heat shrink tubing on the bolt part of the u-bolts, for additional grip on the round crossbar.
To remove the ARB awning. Just REMOVE the 2 BOTTOM channel nylock nuts and bolts(see them upper left on pic) on the back extruded aluminum bracket. Then LOOSEN the 2 TOP channel nylock nuts. This now allows the bolt heads to slide in the channels. You then slide the ARB awning forward to remove one end of awning off the mounts. Then slide it backwards to slide it off the other bracket. This leaves the brackets mounted to the roof rack cross bars.
Do the opposite to install it. About 3-5 minutes to remove and 5-10 to install
You can do this by just LOOSENING ALL four bolts and nylock nuts, but it is very difficult to slide ALL four bolt heads in the channel without binding. Tolerable when removing, but a bi*&ch when trying to install it that way.
I like the awnings. Made fairly sturdy. Have not had a chance to use them yet. Just installed them.