Review on 🔥 First Alert PR710: Slim Photoelectric Smoke Alarm with 10-Year Sealed Battery – Enhanced Safety and Longevity by Mike Snedeker

Returned it after working with it for 2 days to try and attach it to the base. There are 3 slots that correspond to 3 tabs. If it doesn't rotate far enough to turn it on, the device will fall to the ground. I found a replica in my basement and found that when the activation tab is pushed up (as instructed) a plastic finger pops out sideways and this keeps the tabs and slots from snagging. If you pull the tab outward, it will pop out and the device will connect to the base as intended. The instructions say nothing about this. If you're curious and mechanical, buy it, otherwise find something else.