I cancelled mine today because it's a ripoff, but I noticed they include ORP now:
Guess we will see if they take away an included feature..... this seems "new". When i cancelled, it warned me I would lose a list of things, and ORP was one of them.
After you replace the batteries, charge them every so often with a correct AGM charger such as a C-Tek. The alternator will *never* fully charge the batteries as it cuts off too early.
The 850 is 1 of 2 standard fans for JTs, comes with the Diesel and any JT with tow package. 600 otherwise. The 240 alt comes with anything with the 850 and anything with Aux switches.
I got the older Jackers with the .75" and 1.25" options. I am 6'2". I used the .75" option and it worked well for me. Did not affect anything other than my comfort going from "I hate these seats" to "these are fine". I would slide forward in the seats with the original configuration.