Here's what mine looks like:
EDIT: I realized after I posted that I hadn't converted this rule to the 'sleek' design. It is now 'sleek.'
Since I have hub security enabled, I can't use the http POST method, so I'm using the Hub Controller Driver from here: [RELEASE] Hubitat Hub Controller .
I do power loss notifications in another rule (that encompasses more Range Extenders than just this one,) so you would have to add notification if you so desire.
Of course, I don't think I've had a prolonged power outage since the one where I depleted the main UPS battery and had an uncontrolled shutdown, but I have tested it successfully.
If anybody's curious, the 12 hour delay comes from me using a dedicated UPS/power bank for the HE hub. It's this one from Amazon: https://smile.amazon.com/gp/product/B00ME3ZH7C/ . I've tested it beyond 24 hours of uptime.
