I see 3 options on our forum store.
TrueAm UTV-SBI-CM UTV Dual Battery Connect & Monitor Kit
This is everything you need to add a 2nd battery, minus the battery. Includes wiring, a relay and a dual voltmeter.
TrueAm UTV-SBI-CK UTV Dual Battery Kit
Kit above, minus a relay, dual voltmeter etc. This would probably be the more popular option being sold.
TrueAm UTV-SBI-18 Dual Battery Isolator with PEP
Basic iso with nothing else. If you have lots of spare power wires in your garage, this would be a good option.
If I were to do it again, I'd buy the first link and not worry about anything else.
Start a convo with
@Hondasxs for the best deal.