Electric locking rear differential.

https://www.youtube.com/shorts/Ls3SViVLHbo

Part number Q870-330000 fits many different machines. I sent email to European dealer about buying one & shipping it to usa, but they never responded 

https://cfmotoparts.eu/2022-atv-cf800atr-3-rear-axleon-cammand

[2015 Z Force 800 53/Trail EPS]

Yeah that should be a standard everywhere as although they use them on paved roads like cars more then us, we do also.. but having a "Turf Mode" has been a good selling point for others like Polaris.

Agreed. There are alot of hard pack dirt roads & trails where having an unlocked rear diff would reduce stress on the axle shafts & reduce tire wear. Just lock it when possibly needed, same as the front diff.

I don't need, or want computer traction control. My machine has 3 stages of manual traction control:

Stage 1 - throttle / brake
Stage 2 - activate 4wd
Stage 3 - lock front diff

A locking rear diff would give me 4 stages of traction control 

[2015 Z Force 800 53/Trail EPS]

Maybe as more states allow these on the road they will start having them here as well.