So fortunately for me (unfortunately for you) I bought mine from Blue Monkey, which included the harness to make it completely plug n play but it appears they are no longer in business.
The actual device is called a Speedohealer made by a company called Healtech. You can still get the device on ebay
https://rover.ebay.com/rover/1/711-...0001&campid=5337789113&icep_item=303478361327
But you'll have to wire it in on your own.
I also put in a new transfer case chain while I had it apart, and replaced the input and front output seals, the oil pump o-ring and filter screen.
And then there was all the rear suspension stuff to get the pinion pointed correctly - Savvy aluminum adjustable upper control arms and a JKS angled track bar bracket.
My transfer case shift linkage was jacked up and I got tired of messing with it so I made an impulse purchase of a savvy cable shifter. Totally unnecessary since I'm still on a stock skidplate but when I go for the tummy tuck, it'll already be done and I won't have to touch it.