airsafe hitch

Thats a big rig!
I will explain as best I can, its not straight forward.
You probably need both to make a complete towing system. The airsafe hitch (on mine) is a class 6 hitch, and goes straight in the Hayman Reece type tow bar frame bolted onto the truck. You order it with an adaptor plate specific to the coupling you are using. So I ordered mine with an adaptor plate for a (Vehicle Components) DO45. The adaptor plate (they supply many choices) was predrilled to suit the pin from my DO45, which was, at the time still bolted to mu old hitch - the main part, the swivel etc, was already on the bushtracker van.
I removed to old hitch, inserted the Air Safe, put the pin in, and then followed the instructions. Hardest thing was getting the pin from the DO45 out of the old hitch.
The adaptor plate was then placed at the correct height and fastened with 6 bolts - there is some scope for height adjustment.
I lowered the van onto the pin, and checked the air pressure in the airbag, 11 psi, and too low. I pumped it up to 32 psi and it rose to the correct height, about one inch from the top.
Sounds complicated, but its easier when you are doing it.
And no, you dont have to do this every time, the hitch stays on the truck, the coupling stays on the van, and the air pressure stays the same essentially, maybe check every once in a while if you think the tow height is low?
But its how it tows makes it worth while. Very smooth, very stable, takes out all the nasties.
And the DO45, this coupling is very strong, the body is a solid piece of square steel drilled out for the barrel, I cant see it failing. Easy to use as well.
Together, the hitch and the coupling work to get rid of the severe shocks that trucks transmit to van A frames, over the years there have been many instances where A frames have broken...
good luck

Agree with the above
We have the 6000kg Airsafe on our F250 (which has a F350 rear end) towing a BT.
The difference in ride is significantly improved for both the towing vehicle and the van, with all the shock loading dampened. After the first trip, I retro fitted the shocker set.
Once set up, I find that the air pressure does not need adjusting for most of the time. I usually check it after the first hour or so to confirm the setting.
The van has a DO35 and the only thing I needed to get the Airsafe suppliers to do was fabricate a new rear plate as the clearance on the first one was not sufficient for the hitch block with the grease nipples fitted on the outside.
While initially expensive, it is obviously far less than the costs associated with a broken A frame and internal damage to the van.
I would not go anywhere without it fitted on this category of tow vehicle
Cheers
Andrew