This may not be the exact model, but I bought 2 First Alert detectors at Costco for $23. Not a lot to installing any smoke detector, most have two screws that go into the ceiling and a cover that pops off so you can replace the 9v battery. Sounds easy enough, but getting the screws in the right place isn’t always simple and its always hard to remember how to pop the cover when you do the battery change (twice a year if you do it right). This one takes care of both problems. There is a separate base that fits a variety of existing screw patterns and if you don’t already have screws in the ceiling, you can just hold the base up and mark the location for the holes perfectly. Mount the base, then the detector gets fastened with just a simple quarter turn. The battery (AA below, but 9V in mine) is in a pull out tray. Pull out, change battery, push back in, done. It’s not a Nest Protect, but it works out to be $235 cheaper for the two (which doesn’t mean I may not buy one, just not today).

Thinking you haven’t changed batteries lately? Go do it, you’ll sleep better knowing it’s done.