Not exactly RAM only but I remembered I bought this undercarriage power washer attachment from Amazon for around $30 or so a couple years back.
This is just a power washer attachment with quick release connector, it does not spray soap or anything although I am certain if you do some modifications you can use the foam cannon with it.
This is good for power washing the underside of your truck if you go through mud/ snow/ offroad/ general cleaning. This is also a very good idea if you do your own oil change and stuff.
However, if I was to buy this again, I'd go with something that has bigger wheels so it's easier to use, and something with more nozzles. As you can see, my left side nozzle is on its way out already after no more than 30 times of usage.
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